Question about transplanting before flower

Hi all-- my question is about transplanting before flower. I have the below photoperiod (my first!! previously just autos) and I had originally thought that I wanted to run it in a 1.5 gallon pot (photo bellow). My initial "idea" was that it would be manageable enough to let me focus on trying some new techniques (...and I may have been watching a lot of cannabonsai videos on youtube). Now that I'm ready to switch to flower, I see that this may not have been the best idea. The 1.5 gallon pot is basically going dry every 8 hours-- she's a hungry plant!! My question is, if I transplant to a larger pot, say 3 gal, about how long should I wait before flipping to flower (or should I wait at all)?

Details:
strain: Ninja Cookies by Beantown Greentown
medium: 80/20 coco/perlite (feeding almost every 8 hours to run off)
nutrients: maxigrow (btw-- this was absolutely one of the best tips I've picked up on the forum. If you're a new grower, HIGHLY recommend)
light: 250w led
age: germ on 12/13

Thanks!!!

You can transplant, wait a week and then flip to flower or just do it right all in one swoop. Depends on how much patience you have.

I try a minimum of 5days after transplanting before i flip...ideally 7 days but ive never been that patient to make it to 7.

Makes sense. Thank you!