hey Gordon, I am probably by far not alone in wanting to do TRT using the 11.7mm rope(s) I use daily in a variety of situations. There is no device out there that will do it, which why folks are stuffing 8mm lines as a sort of hack. Can you make that device ??
With rope diameter that thick (not saying it’s a problem), you’re likely to benefit from using two Independant devices. I have a myriad of reasons, but The main one being: using 2 separate devices allows Independant orientation if the ropes are used as 2 sepeerate stationary systems.
To get into TRT with larger diameter ropes, you might find that you already have what you need. I’ve made a video years ago of tandem hitches, each with their own hitch climber pulley, and held side by side with a single, wide HMS style carabiner.
To ascend, I found that I could either footlock in 1:1 efficiency, or move around exactly as I would in a typical MRS by just pulling down on one side and running it through the hiych.
To descend, I found that I also had the choice of pulling down on both hitches simultaneously, leaving the ropes stationary (SRS), or again, just pulling down on one hitch and allowing the rope to flow through just one hitch (MRS).
Example: to climb a 100’ tall tree, you’d want 200’ of rope for a MRS. To climb the same tree with TRT, you can use 2 separate 100’ ropes joined by a carabiner. By keeping the carabiner at the branch union you’re hanging from, you’re also keeping the rope equal lengths below you. I kept the crab just to the left side of the union,
This was about ten years ago, so I don’t know if the video of all this is still up, but I did have a quick demo of the whole thing at one point. It’s a fully ANSI compliant merge of SRS and MRS with simple off the shelf components, and it works beautifully. You can use it with a Ring to ring anchor, or simply over a branch.