I set the more promising ones to be higher, simply to try to not rely on the mare's production as much and to give them the best start to place on the LB. I think high initial placement is more memorable than climbing later, so I'd rather they place as high as they can and then they can settle later.

I know that there are well producing EWE combos out there - my first homebred WWW came from one actually -, but it's easier to end up with bad production with single W combo than WW+ mares. Mostly because people usually don't send their best mares to freshmen studs.