It would depend on your draw length. With that much reflex, it will maintain a string angle less than 90 degrees, and be more efficient, at shorter lengths. 58" would be easily done for a 28" draw, even shorter if you kept the length of the non-bending handle section to a minimum... and hence maximizing working limb length.
No formula that I've ever seen. How it all shakes down depends on enough other design specs that a formula wouldn't be much more than a ballpark anyway. The best thing to do is make your best guess, then keep records of each succeeding bow for future reference.