Wow! Lots of replies while I was at work!
I’m not replying to each individually, but here goes.
Yes, this is the HDR collar. The sheepskin can’t be moved up or down, but I can change the length of the straps that attach to the d rings, girth, and under the belly and there’s a lot of elastic that has a pretty good stretch.
The girth can’t go above the girth keeper - not enough room. I can try tying the strap to the keeper though, to see if that helps.
At the start of every ride, the strap is as high as it can go. It shifts down over the ride. The saddle doesn’t move while riding, unless I take the collar off or use a 3 point - that usually results if having to get off several times to fix it.
Girth is tight, and I only have 2 billets.
I’ve not heard that it can effect jump form - but looking at the picture, I’m not surprised. He doesn’t seem to mind it as much as the saddle slipping would though. Not even the gel sticky pads are enough.
Here’s some pictures - https://imgur.com/a/MqJkDhO. There’s the original image, one immediately post ride with the saddle and everything in the same spot as when I started, and one showing how the monoflap prevents the “usual” placing.
Here’s some video - to give a better idea of how he moves. He is pretty athletic and has fairly decent form, I wonder if he’s just too “big” for this type of collar. https://youtu.be/pQDou5yWpn0