I'm in the same situation - I'm designing a Yost-style SOF kayak and wanted to use software to generate the bulkhead patterns. I decided to use Kayak Foundry even though it doesn't do hard chines (but it is free). I designed a hull I like and am making a SOF scale model with the patterns, and will adjust the location of the chines on the model by eye and by testing. I'm still in the process, but have cut the bulkheads. The chines I will set by eye and recess them in the bulkhead outline to the point that the flat hull surfaces approximate the curved hull in a way that preserves the hull volume, as far as I am able to estimate it. This is working so far, as it is not a really hard-chined design. If you only plan to do one boat and are not insistent on getting drag estimates ahead of time, this method may work for you as well.