One of us is wrong so there is no way we both know what we are trying to say. And I think we started to over educate the kid with info. Just keep it simple and get a good base!
Yes your right w9 will allow more fuel to enter at the same Throttle position and your main jet will kick in sooner.
Also running w7 on the bottom clip position is almost like a w9 on the first clip position but they are different.