Finally some more progress... I've been struggling trying to figure out the best way to mount the footholds. I think the best option now is to foam everything and just form it around the holds. That way I can fiberglass them in.
Funny thing is I decided I would go with XFT's because they'd be easier to install, not realizing that a RN and SN tray was different.
However, if these will keep my feet in place it'll be worth it because all my major injuries have been caused from slipping out of the holds. Even when I was jumping high and had clean landings in Daytona, I was slipping out of the holds on landing and chewing up my shins.