Ive built quite a few wooden boards and have made wood fins. If there is no cant in a future fin box you culd simple create the fin in two sections, an upper section which is your main fin shape and the lower section will fit into your fin box. Where they meet you can create the angle you want. Use epoxy to join the two pieces and then fiberglass over the entire thing to make it one complete unit. If you plane the wood thin enough and then build up a couple layers of glass you should have more than enough strength. I have no experience with that type of box so this is all theoretical but making wood fins is not too difficult and they will look far better than any non wood fin you can buy. You should look into making an entire hollow wood board. Its a fun project and there is nothing like riding a board you built from scratch.
Futures bases require a mold with cant, or overbuild the base and grind the cant in.
I made a video of how to make bamboo fins for ProBox (same method for any other system except the base)
It's here on our website