So far, in a 5 gallon I have averaged 5oz, in a 3 gallon 3oz. Weird right? No matter how they were trained or how many shoots left on it has ended up about the same. I have 4 seedlings I am growing for a contest, in 2 gallon pots. If I average 2oz per pot I am giving up on all intense training LOL
So for me, a 4-top manifold and a lot less hassle might be the way to go
As far as the stretch after you flip. From what I have read, Sativa will almost triple in height, indica about double - with no training to keep it down.