Ok I can now report on the performance in a game
As the night wore on they felt got better and better slide and I was able to do some BF slides and some down pushes. Not ice distances mind you, but I did actually over slide once
I expect as the felt softens further the slide will improve even more. Of all the mods and ideas I"ve come up with, I rank this number two (my dangler tying method is number one)
If I were doing it again I think I would have had the felt cover the knee wings, and in fact I am seriously condering making a second pair to do just that, or more likely since I'm a rather lazy sod, just adding knee wings to these.
Also if the felt gets too soft I may need to add a strap mid shin. This would probably have a clip on it and go around my leg like a pad strap. Otherwise I would need to put a slit where the calf wing joins the pad to run the strap through and iunder the leg channel like the other straps.
Another option which was actually my initial plan, was to put a layer of plastic between the inner and outer felt, just to stiffen up the plate so it holds it's shape. However this is just speculation. For the moment they are working really well so I will only make big changes if it does get too floppy as the felt softens.
PS they work EXTREMELY well on my slide board too