I wouldn't use white foam in any combat wing, it's too fragile. Most guys use 40psi blue or pink foam. Personally, I use 25psi pink stuff (foamular 250). (Dow hi-load 40 is the blue 40psi stuff, Foamular 400 is the pink stuff).

I've done nylon by painting the wing with WBP (water based polyurathane), then laying on the nylon, then putting on a top cote, and squegeeing out all the excess. It makes a mess, but works well.

However, personally, I've stopped using nylon (or polyester), I've gone to just using tape. It doesn't shatter like monokote, as the overlaps and edges keep a tear from travling, it's light, and is extremely easy to field repair. (I find nylon and polyester harder to field repair. Not impossible, just harder).

But there are so many ways to do it, and they all work well, it's personal preference. I don't think my way is better, it's just what I like.

Oh, on the airfoils, you'd be surprised how well a clark-y type airfoil can loop outside, though most guys find they don't make outside moves all that often.

However, you may find you like outside loops or turns, so you may want a design that suites your style. The airfoil I use suites my flying style and the maneuvers I personally prefer. It's a bit draggier than some others, but I don't depend on speed. And it does dump some speed in a tight corner. However it gives me some extremely tight turns and a very late stall with a very broad CG range, which suites me well.

So, half the fun of designing your own ship is building it to suit your flying style.