New light, how long to accept before flip?

My first grow I was basically in the exact same position, I had a phlizon 180-200w and bought a 240w twin quantum board 301b, for start of flower. I just fired it on immediately and flipped the next morning I'm sure, it's far superior light, also when you flip you lose 6~ hours of light if you've been on a 18/6 schedule Basically the only deciding factor I'd say for you is are you happy with the sizes of your plants for going to 12/12 But if you use both lights and flip, you'll get some big growth during stretch anyway, the more light the better 💪😎