From your dimensions, the Sol Cat boards are wider than the F18.
If you are going to make the boards, do yourself a favor, buy the foam core from a RC airplane company. It will already be shaped and smooth. All you will have to do is cover it with Expoxy/glass or carbon.
Vaccuum bagging will give you a stronger lighter board but a hand layup with peel ply works fine.
As a guess, a NACA 0006 foil will work. Tell them you want a 1/8" skin.
If the foam core is stock, it will cost $US 30-40 for a pair of wings (boards). Custom will cost more.
I have ground foils out by hand and covered pro built ones. Buying one is worth every penny
If you want you can build a hot wire cutter and cut your own cores. Do an internet search.
Carl