I would subject the plants to as few "scheduling shocks" as possible. If you're flipping to 12/12 "soon", I'd start that schedule immediately, with whatever lighting you have right now. Add your new light whenever it comes.

Right now your "master-plan light schedule" can go "veg - blackout - 12 / 12." Going "veg - blackout - veg - 12/12" just throws a extra obstacle in the path to budding. I wouldn't revert to your previous lighting schedule, and then change it AGAIN to 12/12 if this is happening anytime soon. Go for it now and save the girls from an unneccessary shock. :thumbsup:

I am curious about the lighting you have coming, though. Sounds like you planned to use it for both veg and flower(?)

And, am I reading this right? You say your box is 77deg F and it's usually 10 deg higher? That's too hot. 75 day / 65 night is not unreasonable, for example. 81 day / 78 night works for me, but that's as cool as I can keep things. If you are blessed with cool ambient temps, take advantage of it--better yield and easier maintenance. Peace, Hermie :hippy: