Wood is fine provided you get the right size. There needs to be windage, ie the ball is slightly smaller than bore and has some wiggle room so you dont get excess pressure.
Standard windage is 1/40 the bore size.
Powder charge, start small, you do not need a ton. Im just guessing but i bet MAX charge should be less than 1/4 pound, more like 2.5-3 oz, but go smaller. You dont need much for wood balls. Use cannon grade or 1F, again less pressure. Standard formula for max charge is 2oz per inch of bore.
I would not use any wadding or patches, again can cause excess pressure. Put your powder charge in a tin foil package the size of your bore and use masking tape to secure your ball to the powder. A simple X shape, dont wrap the heck out of it, you are just trying to hold it in place. Lightly ram it home to eliminate any air pockets. Gaps and such cause excess pressure. These cannons and their “pounder” designation are based on an iron ball, if you use lead it will be twice as heavy and cause possibly excess pressure. Zinc is good, most balls used are zinc these days.
If you want to do canister style you can use a loose fitting tin can or just wrap your BBs in a separate foil pouch and attach with tape again.
Cannons are no joke so be careful and always think about pressure. Nothing tight like our rifles, or you could be playing with a pipe bomb.
Do your research and start slow n low.