I don't use straps to hold my feet in the holds, and the type/size of the hold not really matter to me because I'm going to pad/turf it to the shape I want it to be. When I do one footed flip tricks my left foot is just wedged in the foothold sideways, one footed rolls my foot is in the hold more traditionally.
But for that to work, the holds needs to be really tight....to the point that I have to more or less kick in. Whenever I have to ride skis that are not mine I wind up having to add lots of extra turf.
On my own skis I run the 25mil padding on the bottom, a layer of the thin padding on the inside of the hold...then at least one more strip of padding along the outside of the hold to make a little lip. Then I shape the area with sand paper....I sand the bottom a little mostly for clearance. If you are close to feeling secure, but not quite there, a strip of turf that acts like a little ledge will go a long way to making you more secure.
And when I'm riding boats where the holds are too big and I need to tighten them up, a few layers of turf placed so there are some ledges for the top of your foot to grip will work well.