Fox farm ocean forest and its 5 weeks since it broke ground as a seed but I'm sure most will be male anyway. Either way they look a bit small to me to flower yet I was gonna go probably another 2 weeks before I Flip them since I'll probably end up getting rid of most of them but yeah the 3 gallons will probably the flower pots.
I go into 3 gallons pretty quick. My plants are only in 1 gallons for a couple weeks. Here is a pic of one in a 1 gallon about to go into a 3 gallon.
So anyways I would go to the 3 or 5gallons as long as your roots are coming out the bottom of the 1 gallons and the fan leaves are hanging over the edges it’s time to transplant.
Transplanting from 3 gallon fabric to a 5 gallon fabric would be a PITA imo I would just put them in their final pots now. Either one will work. If you use the 3 gallon you’ll have to start feeding hydroponically or top dressing sooner than if you use the 5 gallon.
my recommendation for growers using FFOF is that they start in a 5 gallon and leave a few inches of space at the top of the pot and top dress with a couple handfuls of soil every time you water.