Well if you've grown OG's, then you're pretty familiar with the capabilities of Sativa growth. The way I keep them from stretching is by feeding low ppm's during first 3 weeks of flower, and feeding ONLY when medium has dried (not til the plants wilting, but just when the weight of the pot lets you know it's dry). Once stretch is over and growth is focused on buds you can start hitting with normal nute dosage and boosters if you use them. I see you supercrop as is, so that is also a VERY handy tool for those stretchy vigorous tops. I think upcanning will actually encourage more outward branching so you should be good with an upcan. But keep them tops supercropped, and tie down even if you must. If you focus on keeping the tops from outgrowing everything, the lower branches will get more auxins (hormones) and encourage them to catch up to the tops, while the tops get less auxins and stretch less.
