SO here is a blend attempt.Between each revolve is a blend that works well, but your left with that middle hole. Is this a part we cant do without "N-Patch" or is there a way to fill this. I was thinking even of putting in a tiny little surface in the top center and using blend on the four edges again, then just having the little tiny thing at top be a bit rough (Or even fill it with a new revolve tent, like a vent top).

Anyway, seemd close except for this last part which it seems like you were talking about already.