This isn't much of an answer to your question. I live in Kitchener, Ontario and the local plywood specialty store here carries okoume for about $55 a sheet too. I didn'nt buy Okoume for my kayak but used a 3.5mm Baltic Birch ($30) - a good quality 3 ply furniture plywood with good bending properties, strength and ply integrity. It actually seemed to be a superior product than Okoume (if you don't care about the bland birch look). The only drawback is that it comes in 5' x 5' sheets meaning an extra scarf joint here and there. I only used this for the hull, then glass it and painted on a solid colour so I didn't care about the extra joints. For the deck I used a 4 mm birch standard furniture grade plywood 4 x 8 ($30). Also used East System Epoxy from Noah's in Toronto. Liked the stuff. low odour. easy to work. Good luck.