With the size going from 50 to 53, I think most people in that size range could go with either and probably be satisfied with the fit. I was switching out the stem anyway, so I went with a 100mm, instead of the 80. I agree, stand over is not as important as overall comfort, and with so much variance in cockpit adjustment, so I am confident that the 50 will be more than fine. For the person still trying to decide though, it is probably just worth the time to wait and be able to try out both.