If my plan is to go vertical, then I am trying to pull lead before the merge and have that sucker firewalled so I have plenty of E.
When I commit to going vertical, its usually when I know they don't have the same amount of E. I continue the zoom, and at the same time watch from the 6 view to see when they start to fall back, and then begin my rollover into them. At this point, I am counting on them stalling and flopping over and they are now at my mercy.