Flipping to flower?

I would flip right away. The main thing you have to consider is how much height you have. Expect your plant to double in height or more. Your light has to be so far from the canopy or you will get burning/bleaching. Since your doing a bunch of LST a lot of your height is horizontal and once you flip she will start to shoot up to the light. Alot of my grows i have had height issues and had to supercrop to get them down to a reasonable size. Happy Growing