I was playing around in the basement with my HitchClimber with VT setup. The first picture below shows what I guess is a "standard" configuration. Climb line terminated with a DFL and 'binered to the top HitchClimber hole.
I did not like this setup one bit because the termination knot and its 'biner interfere with the VT, so much so that I seriously question the safety of such a setup.
The second picture below shows a 1" nylon sling used as a leader on the climb line connected to the HitchClimber's middle hole. FYI the 'biner is a Mighty Mouse, chosen because of its low height. This is a much nicer setup IMO in that there is a greatly reduced amount of interference. Feels much nicer in the hand and operated better as well.
The third picture is the same as the second except I went even more low profile by replacing the Mighty Mouse with a 3/8" delta link. Obviously if you're going to go this route, you'll have to consider the safety issues surrounding anything that's a screw-link.
The VT is made from Tecnora. I like this particular Prusik cord because it is high temp rated yet has no whipping on the ends (like bee line) to interfere with the HitchClimber.