Just a post-mortem on this thread. I've now moved my cleats to a position intermediate between their original position and the position I had for the ride in which my legs were hurting. I also lowered my seat just a bit. The leg discomfort has gone away, and I think I have just a little more power (especially out of the saddle) then compared to the original position. But I don't think I have it perfect. So now the strategy is to make small modifications until I either find the perfect position or get tired of experimenting.