Sounds like hot foot, which is discussed here fairly frequently. From what I've read, your weight should ideally be evenly distributed between all three points of contact: bars, pedals and saddle. But hot foot's got more to do with your shoes &/or pedals/cleat position than with your saddle.

There are a few threads in this Search result that might be helpful for you: http://forums.teamestrogen.com/searc...archid=2611548