I think I would modify John's statements just slightly. He says "You want to both fly faster and be choosier about thermals going to an upwind turnpoint, and fly slower and take weaker lift going to a downwind turnpoint."

I would say, you want to fly faster 'after the last climb going into an upwind turnpoint' and be choosier about thermals (particularly the last one before the turnpoint) when going to an upwind turnpoint and 'be more willing' to fly a little slower, or take a weaker climb (particularly the last one before the turn) when going to a downwind turnpoint.

Key is that theory is different when trying to maximize altitude over the ground at a fixed point some distance away then it is to maximize achieved cross country speed through the air.

Sound about right, John?