If they are already in flowering i honestly wouldnt worry about anything. Transplanting during flowering, although totally doable, not recommended. I dont know how true this is but i read somewhere that new roots are made for new growth(aka veg) and that flowering isnt really considered new growth. So your plant should already have all the roots its going to need to finish. Just keep a close eye on them and if you see signs of them becoming root bound, then think about transplanting.I checked, they are 3 gallon containers. I put them to 12/12 when I transplanted so, basically it took a week for them to dig roughly 9 inches to the drainage holes. I checked again this morning and now all the plants have roots showing out of the drainage holes. Should I stress, or will the plant take care of it herself (cut off those roots that have seen air/light and use different ones for functions? Thanks