I think Fujimo is right on. My first thought is to use a proven design, second thought is Supertiller.
At the end of the day though, if you don't have the time, space, budget, desire to build at least a few bows then creating your own design is probably not the best idea. It's gonna be hard to nail the stack thickness first time to get the draw weight you want. Taper can be pretty well calculated in Supertiller, but as you can see from Jim Thorpe's build along, the first bow was not perfect, it required some design changes to get it spot on. That's a guy who's been building bows for 30 years too ...