Pot size for flower?

Your doing a great job on your first photoperiod grow. The plants are looking A+ Your could flower in your 5gal pot if you want. Its all about when you switch them to 12/12 and what you want to do with the plant. The larger the pot the larger the plant can be, it also goes the larger the pot and plant the larger amount of feed you will also need. If you plan on doing SCROG I'd suggest a 10gal pot. I don't know how much vertical room you have in your grow, but a 15-20gal pot would let them weeds grow to monsters in height. Your defiantly don't want to outgrow your space in flower as it harder to go higher with the lights if there is no more room, then your plants get burnt from the lights. Your grow is looking great and anything you do I'm sure will be fine no matter what. You have a good handle on what your doing. I would suggest transplanting into the new pot a week or two before switching them to flower. Happy Growing!