I don’t have to have taken a factor two fall to understand them. Furthermore, experience climbing multi-pitch does not automatically translate into automatic knowledge of the workings of a factor two fall solely from the act of climbing multi-pitch. Only experience catching or taking factor two falls is valid for that class.

To respond to your first question of belay from you harness or directly from the anchor in a lead belay situation belaying directly from the anchor can be very dangerous. If the leader successfully prevented a FF2 by placing one single piece capable of holding falls above the anchor the direction the rope will pull your belay device is up. If you anchor is not designed for an upward direction of pull in addition to a downward one the force of just about any lead fall will rip your anchor straight out of the wall and both of you will plummet to the ground. Of course, it is fairly easy to build an anchor to withstand upward pulls but if you are new I'd say better be safe than sorry and always lead belay of your harness.

In terms of this whole changing brake position for FF2, I don't have any experience catching them, but it sounds reasonable. However, some things about FF2:
1. don't take them
2. they are easy to prevent; fall factor is reduced by climbing high and placing protection (FF=distance fallen/amount of rope between climber and belayer). even clipping a piece of your anchor before leaving it will reduce you fall factor and prevent any need to change your brake position. clipping this anchor piece does not mean you should then run out the climb for the first 30 feet, place another piece ASAP. the difference between FF1.9 and FF2 barely exists.
3. just because a leader falls below the belay it is not necessarily a FF2. the leader must fall directly onto the belayer, no protection what-so-ever
4. just don't take them. the force generated has the ability to rip some of the most bomb-proof anchors straight out of the wall. once again sending both of you plummeting towards the ground

As for the hand position, consider first of all what happens during the catch (based on thousands of trials, filmed in high-speed video, by the CAI).

On the other hand, if the belayer belays palm up until the rope is clipped through a bombproof anchor point and brakes by bringing the palm up to the chest, then they get the benefit of the longest possible inertial stage under the circumstances and, with the hand arriving at the device from above rather than from the side or below, benefit from all the friction the device is designed to provide.

I do want to make it clear that the CAI did not test factor-2 falls and all of this is supposition. In the absence of actual tests, which will probably never be done with human belayers, wearing gloves, belaying palm up, and braking at chest level until the first piece is clipped seems to me to be the most rational approach

If there is a high risk of a fall before getting the first gear in the next pitch, or if the gear is not good, the belayer can hang say 20' below the belay anchor, tethered by their rope. Then the leader clips the belay anchor as their first protection (they can use a "screamer" type load-absorbing runner when they clip the anchor also). This avoids the problems of a factor 2 fall.

NA, some videos were shown, I think, at a presentation made at an Alpine Club of Canada meeting. I think I might have a link on my other computer, but that is only to a transcript of the commentary.

If you read Italian, you might be able to get a lot more information from the CCMT site http://www.caimateriali.org/

This is a brilliant idea and I'm shocked that I've never heard of it before. It has two benefits, first it allows more rope into the system meaning that it is effectively no longer a factor two fall, second it provides more room for the belayer to get lifted upwards effectively limiting the force. This isn't something I'd do every time, or ever for that matter, but in the event of a sketchy belay without gear over it this could definitely make a huge difference.

The website link you posted is forces exerted while using a screamer. And yes, it is true that using a screamer between the belay and anchor will significantly reduce the force on everything in the system; it's what they are designed for. However I'm talking the most-simple three-piece anchor, no screamer. FF2 generates the most possible force on a fall. This is physics. When a FF2 takes place the fall is directly on to the harness of the belayer, true, but without a screamer no ripping or dynamic belaying occurs and all that force is then transferred directly to the anchor.
I don't want to explain the physics behind forces in fall factors, I'm a climber not a physicist, and honestly they are way over my head. Maybe sometime I'll find them online.

So I was poking around for information on the pros and cons of lead belaying off the anchor (with the belay device on the anchor, not the belayer's harness, if I'm using the wrong terminology, please let me know.)

In practice, I have asked my leaders what they want me to do, and every time, they tell me to have the belay device from my harness, and me into the anchor so that my body will help absorb the force (?) in the event they fall. This makes sense, and it's what they want, so no problems.

However, upon trawling the interweb, I found this in regards to falling before the first "jesus nut" (just finished The Book!) is placed...

- from supertopo I think...

There is a lot on rc.com on this subject
http://www.rockclimbing.com/...s;page=unread#unread

This is a table from YATES and its pretty good.
http://www.yatesgear.com/...ing/screamer/use.htm

Thats very dangerous thinking. Tell that to every new belayer that has dropped a climber using an auto-locking belay device. Most commonly, when a climber is dropped from an auto-locking belay device the belayer follows this process:

1. Climber gets to the top of the climb and is ready to be lowered.
2. Belayer opens the brake and the rope starts to slide through the belay device.
3. The rope starts slideing through the belay device too fast.
4. The belayer gets minor rope burn and starts to panic.
5. The belayer pulls on open the handle as hard as she / he can forgetting that the harder he / she pull on it, the less friction the device produces.
6. The feed speed of the rope becomes dangerously excessive and the friction produced by the belay device becomes increasingly smaller.
7. The belayer tries to control the feed speed by squeezing the rope harder.
8. The belayer instantly sustains rope burn and lightens up their grip on the rope to eliminate the pain.
9. The climber hits the ground.

It’s always the same. I have seen it many times and had it happen to myself once. The only thing that saved me was yelling “LET GO OF THE HANDLE!!!!!!!!!!!”. Fortunately my belayer was not a complete moron and did what I said which stopped my 35 foot free fall instantly pulling the belayer 10 feet into the air. When I got to the ground I asked her what happened. She said "the rope burned my hand and I couldent hold on".

The problem comes in when a belayer grips a rope that is moving at high speed. Squeezing any rope that is moving at high speed will cause instantaneously severe pain and to think your belayer will “just ignore it” is very dangerous thinking.

What book have you finished scarlett? In Climbing Anchors, it states that a belay anchor is not yet completed until the jesus nut is put in. If there is any doubt in your climbing ability, above the belay anchor, or you don't see a spot right off the belay to place gear, then you should consider letting your, hopefully more experienced, partner take the sharp end. As a last resort rap off.

It is called a direct belay.

With a grigri directly on the anchor, you wouldn't have the braking position problem, but you'd risk exposing the anchor to a nearly complete static catch of a factor-2 fall

Jay

NA, some videos were shown, I think, at a presentation made at an Alpine Club of Canada meeting. I think I might have a link on my other computer, but that is only to a transcript of the commentary.

If you read Italian, you might be able to get a lot more information from the CCMT site http://www.caimateriali.org/

Actually, with a 10.5 mm rope the GriGri will slip on a factor one fall when belayed off the anchors. The GriGri will slip enough on any fall with a 10.5 mm rope to limit the force to around 5 kN as shown in the user manual of the device. So if you took a factor two fall right onto a GriGri that was mounted to the anchors with a 10.5 mm rope the device would slip when the peek force hit around 5 kN. If you were using a thinner rope, the device would slip sooner. Although that’s not as dynamic as a plate belay device, its more dynamic the relying solely on rope stretch to stop you.
Although thats not as dynamic as a plate belay device, its more dynamic the relieing soly on rope strech to stop you.

I've never clipped into the anchor as my first piece, I always set something within the first few feet of the belay anchor.....That would put all of the falls force on the anchor wouldn't it?