Swey, when designing for developable surfaces, you are pretty much obliged to accept the stem shape that results from your choice of chines. Same with the keel line or rabbet line. If you want to work some curve into the stem then the panel must twist as it travels aft and you have to then develop the curvature that results in each station cut using paper and pencil techniques such as referenced below. Once that is done, you can stuff it all into freeShip and see if it agrees that your panels are developable.