Using El Hefes also but other Ride bindings.
My local shop as all in stock Ride parts. Something very useful. Broke 3 just this year so very handy. Small parts easily changed.
As for large boots, all my boards have risers. I guess you need +27.5 waist to eliminate boot out on a 29.0 boot with 25/15 angles.
One thing I really noticed. The narrower boards are quicker edge to edge. More nimble and I like it also on some boards.