Building a longboard - Need some educated insight on details!?

Me and a couple of my buddies actually have a longboarding making business so i have some good ideas for yo. First off you need to consider flex. For a very flexy board, which is good for carving and cruising, i would recommend 7 ply of 1/16 inch baltic birch or maple verneer. Now as for specs, well i would ain for about a 37-40 inch length for just mellow cruising and 34-38 for a tight carving board. I would make the widest point about 9 inches (not trying to be sexist but girls generally have smaller feet so a big platform isnt necesary) or 10 inches if you have larger feet, maybe like a size 0-6 for a 9 inch and 6-1000000 should look for a 10 inch wideness. For shape design, i would look at the original apex 37, apex 34, or pintail 37, or pintail 40. Hope i could help!