I'd figure the radius or bend needed and than bend an oversize piece to that radius, then trim it to fit, instead of trying to cut the perfect shape flat and hoping it would fit after I bent it. I hope that's what you're trying to do Chris. Trying to lay that out and cut it flat so that it fits after you bend it strikes me as an exercise in frustration, but then there are quite a lot of exercises in frustration in boat building... good luck.
Best, Bob
S/V Restless