I dont know, what you are missing drsurf, as others have said, you gotta do it yourself and get some experience till you know, and I only talk to my friends learning it now.
I got high lifting wings for kitefoiling, but not more than the typical 12-1300 cm2 size/lift ones, as bigger do not make sense for me being average weight.
And got a useable board (not for kiting), think its 120 liter that fits the box.
Can borrow a wingsurf wing from a friend living nearby, but would of cause prefer to use my own wing and foil, as borrowing other peoples foils on something you are new to, is often a no no, at least I would try to avoid it.
This is why it is interesting for many I think, if you can use existing gear and try it out, instead of investing.
OR, if you can learn on a big wing, and then use your own kitefoil big wing later, instead of using a beginner/low wind wing (if this exists as such, but it seem the bigger the easier at first...)
Thus the question about wingsurf foilwing size at first
Secondly, a discussion about which sizes are used now, and are there any direction in this early phase of wingfoiling, going up or down in size, or following skill level?