So I'm working on a Subtop Product. 3/4 plywood deck with 3/4 x 3" plywood edges.  I have the depth working correctly, if the OA depth is 24, the deck is 23 1/4. But having a hard time coming up with the correct formula for the length. When I add the finished end it changes the OA size of the product, I'd like to keep the OA size the same. Any ideas/help with a formula would be appreciated.