Yes defiantly put them into flower asap. I like the setup you made but it looks like it will fill up fast your plants are looking vigorous. Turn your light up pretty high if you have the thermal capacity without overheating your box. That will hep the plants from stretching too much by giving them ample light. also good to do in general because the plants need a set amount of light per day and once you flip to flower, if you do not compensate the light to give more photons per second to the plant. over the corse of the shorter day it would have taken in less photon energy from the plant thus making it want to stretch for more light and making more airy buds