Crank length is about your seat position. (not saying that's ideal, but that's how the cycling industry deals with a lot of different leg lengths and token adjustment in crank length)

Basically all cyclists ride one length crank (170mm to 175mm is a token 3% spread). All the adjustment for the huge spread in leg length is done by altering seat tube angles. That's why you have guys with 29" inseams riding 172.5 cranks and a tall guy with 37" + inseam riding 175mm cranks.

That's why 50cm frames have 75-76 STA's and 62-64 cm frames have 72 STA's.

Sorry for the late response I just reread your post.

FYI , I just looked at my seat again--it is approx in the middle of my straight clamp. On my new bike I want less stem and more top tube for better balance.