Tobe Sherrill had his system reviewed by an independent person, Burnham Chamberlain, well versed in the Texas System. Here is the review.
"Today I spent several hours exclusively on the TF system. I made about 20 ascents, ranging from repeated short climbs of about 20 feet, mixed in with 5 or 6 more of about 60 feet. This was a better set of trials than my previous batch...I was able to concentrate on just this and get things matched up to my harness and body better. So here's what I am thinking
now:
I had some learning curve troubles with the Croll, mostly involving detaching it during changeover to descend. But that got worked out, no problem with the unit itself. But I did observe one thing worth mention...I found that the carabiner I used to mount the Croll to my harness sort of blocks the rope where it exits the bottom of the Croll, making the rope take a bend. This fouling of the fair drop of the rope creates a drag that complicates things. I replaced the biner with a screwlink, your part #28737, which has a much smaller profile. I like this better, and it has the additional benefit of not getting as bound up with the biner on the left hand ascender tether. In fact, this may be the bigger advantage.
I think I am going to swap the CMI ascender mounting points so that the foot strap is in the right hole and the tether is in the left hole. This keeps these two lines from always being crossed. You might consider setting them up that way when assembled.
I did adjust the length of the foot strap per the instructions you emailed, and that is about right, but untieing and retieing the fishermans knot is hard after it's been loaded, such that I had to use needle nosed pliers and a small fid to do so...I still think using a fully adjustable foot strap, like part #28750, would be a better choice.
I found that I had to expend a fair amount of strength to keep my body upright, in line with the rope...in my mind perhaps more so than with my Texas system because with the TX I can use the technique I described to swing my heels up under my upper body rather than just hold my position with arm strength alone. But I willing to call that a draw as I'm sure I'll get more competent at best technique for that, and the TF is clearly much faster up the rope, so even if the energy expenditure is equal the gain in climbing speed makes it a better system than the TX. Keeping both hands on the ascender is helpful, but I occasionally kept the cam from grabbing when I accidentally held it open within my right hand grip on the top of the ascender. Careful hand placement should take care of that, but when it happens it sure spoils your rhythm! Speaking of rhythm, a good point in favor of the TF is that it is a smoother climbing motion, imparting less peak loads on the anchor point. The TX generates 2 to 3 g's with each sit-stand cycle, potentially a problem if tie in point assessment has missed something.
Changeover to descent on either the Petzl I'D or the Q8 (my personal favorite rescue 8) was not too hard to work out, and I am now adept at the procedure and find myself fully comfortable with it. Getting better at handling the Croll was the biggest part of it.
So I think you have a pretty good kit here. I think it would be a harder system to teach to climbers new to ascenders than the Texas, but perhaps not. The Pantin can be a challenge to some for keeping it on the rope, but a keychain biner handles that. I've had pretty good luck with folks that are not as strong in the upper body getting the TX to go for them, and I wonder about that with the TF, but for those with the arm strength to keep upright I think it has definite advantages, primarily the superior speed."
I did have the opportunity to try the system at the 2005 Gathering. I will post my comments later.
Waving from a treetop,
Peter Treeman Jenkins