an address that might be of intrest
universidad de león ,
departamento de biomecánica ,
Dr. Juan Garcia López .
this is the guy who´s working with some of the best spanish cyclists to improve their position on the bike ( Mayo , Valverde among others )
some general rules he´s come up with are that leg extension should not exceed 150 degres and ankle rotation not exceed 20 degrees . ( it seems the pros tend to have their saddle too high just like the rest of us )
aside from that it seems to be more your style that determins position on the bike than size
ie , saddle forward for high cadence : TT and track persuit etc
saddle back for lower cadence : cyclo-cross ,mtb , and rough roads ( paris - roubaux type cobbles ) or just poor roads on climbs .
general road riding : something between the two that feels comfy for your style