Welcome Dr Attaway
I did pinch your document I found online and posted it in a thread somewhere, glad you didn't mind.
I see from your ppt that when frictions is broken we get jerky movement, in our case we bounce down not up.
The problem with many mechanical friction devices is they are not smooth, we muck around with minor adjustments not abseil great distances unless it's cuppa tea time!
But seriously, trying to eliminate that bounce factor when friction is first broken would be good. Believe it or not the hitches we use on 2:1 rope systems do a good job of this, not a lot of bounce.
The real problem also is advancing these devices for the climb up, for instance, a figure 8 would be a right PITA to try and advance if you just want to move up and over a limb.
Perhaps for you to get an idea of what we do in a few methods view the video in this thread, you'll see the advancing issues.
Spikeless DRT access, trunk walk etc. Featuring Brother Colin.