rhm

Standover is a quick and dirty measurement that gets a rider to approximately the right size bike frame. If you can't stand over the top tube, the bike is definitely too big for you. If you can just barely stand over it, the bike is probably still too big. Once you get into the neighborhood of the right frame size, you still want to play with saddle height, bar height, crank arm length, whatever, to get the riding position right. That's where the important fitting is done.

I've discussed sit bone width elsewhere. It's not completely irrelevant; but it depends a great deal on the rider's position on the bike, especially the angle of the pelvis relative to the saddle. Until you determine that angle, talk of saddle width is just noise.