A lot of it is probably subjective (which doen't mean pointless) , and as p ointed out, dependant if quantifiable on rider anatomy.
BTW "Q" in French is pronounced exactly the same as "cul", the French word for "backside" (or a less acceptable slang variant of the word), which lead s to the point of saddle width and position, which would have an effect on leg splay, which would interact with "Q".
Therefore, another monster rears it's ugly head, as "Q" factor interacts wi th "crack" factor. Anybody have a formula for that one ?
Nick March, Agen, 47000 Lot et Garonne, France