Since I've been growing them the last year or so, and doing it in an "all organic" way, I tend to have to wait about 7-9 weeks of veg to get them trained and flat, plus de-fanned, primarily because of height restrictions in my room.. I'm doing it a little different this time, and hope to veg about 6 weeks, max..
Topping and super-cropping tend to be my favorites for training photos, as well..
***EDIT*** I should have mentioned.. I typically veg my photos out as long as it takes a run of autos to go, and then I flip.. Perpetual harvesting for life!!!