RE: VFT, Parallel Limbs, at what point...
It' s not so much the angle itself, altho that does come into play...It' s the overall configuration. Cam design, brace, ATA---all have a part. It does get very technical and varies from design to design.
Remember, one can have too " flat" of a limb also, and that will also rob performance. To find the exactly perfect combination for a given configuration takes much trial and error. Pinwheel 12