I recently gave a belay from above to a group of five people who were all doing the same single-pitch climb and then being lowered off. (In this case the reason for belaying from above was that the climb was too long for top-roping from the ground with a single rope.) I was using an ATC Guide in guide mode, directly off of an anchor. Afterward, I went back and researched different methods for doing the lowering. Any comments on the following methods, or suggestions of other methods?
Don't even lower people in guide mode. Reserve that for emergencies. When the climber gets to the top of the climb, have them clip in, then switch the belay device to normal mode and lower them off. This requires redirecting the brake strand like this: http://www.climbing.com/skill/lower-away/ . (If I'm understanding correctly, the redirect is necessary because otherwise you would need to pull up on the brake strand to brake. That's both physically more difficult and contrary to your muscle memory.) You can attach a backup prusik to your belay loop.
BD's instructional video http://www.youtube.com/watch?v=KM5c9wlTReo shows the technique at 2:37. They show the belayer using her hand to pull down on the release cord, which has been redirected through the anchor. I found this technique to be extremely fatiguing due to the large amount of force required from my hand. They also show a Munter tied to the harness used as a backup.
This instructional video http://www.youtube.com/watch?v=G3zOisWbuB8 shows yet another technique. There's some discussion here: http://www.mountainproject.com/v/anyone-have-problems-lowering-a-second-with-atc-guide-or-reverso-in-guide-mode-/106715350#a_106718389 . He ties the release cord to his harness, so that his hands are free and he can apply the force to the release cord by using his body weight. He then has both hands free, and can use them to tend a Prusik backup.
What do people think? I haven't tried method 3. It seems nice, but I'm worried that in the event that the belayer slips and inadvertently puts his body weight on the release cord, the only thing saving the climber's life is the Prusik.
In the BD video, they show a Munter rather than an autoblocking knot such as a Prusik, which seemed odd to me. After some dialog in comments with Shem Seger, I'm going to write up my attempt to analyze this issue in an answer.