I went to the hardware store this morning and bought a metal ring with screw closure to use instead of the carabiner link from Black Diamond. I forget what this part is called....it's found in boat hardware and starts with "M." You'll see what I mean here .....
https://flic.kr/p/NLYMCS. It may not be perfect, but it slides, won't break, and the threaded link allows the Perlon loop to be secured within the ring. I also bought a boating line connector with a spring-loaded clasp (in the same photo.) I may use this after I have time to saw the stem of the carabiner and remove it. The connector may then fit through the hole where the stem was, and then I can use the original sliding buckle part.
Also the RRS clamp I use has a 3/4 inch slot in the back, and if the webbing I used to make this rig was a bit thinner it would slide easily through that groove. I've been thinking of buying a Peak Design 3/4 inch camera strap that has a quick release length adjuster, and that might fit the backside groove. Here's a pic of the clamp....