I would not be messing with em after flower cause why would you want to stretch instead of swell???Wait for experimenting after you have mastered growing inside unless you have proven data that it would make a drastic change which i dont see happening.Learn the right way b4 you start experimenting are you could end up very dissappointed.I learned this the hard way by trying to go 13 to 12 and my plants started going back to veggin cause i didnt fully understand.I was trying to get 1 more hr of light instead of dark from a thing on youtube,and i now dont play around with what i know works well just trying to get a little more, remember the ol saying KISS,keep it simple stupid, was a ol hippie term for just let it grow its only a weed.And when you try new things dont tryit on your hole op,like additives and snake oil stuff cause ppl dont always tell the truth when the ol mighty dollar is invoved.Things i have told you is from me doing not reading,and yes there is alot of stuff to do to get a little more but like i said its not worth loosing your hole crop are even a plant.IM still waiting for you to ask me a question that i was for sure you were gonna ask....But keep on reasearchin thats how you learn my friend.If i were you id be tweaking my lighting and might look into this HIGHER TEMPS WITH LIGHTS OFF.IF you have a drop of more than 15 degrees when you lights are off its gonna really affect your plants.And your on 24/7 now, i might do a test some how to see what your gonna be dealing with when you go to flower.... Have you thought about this..... and being able to keep warm after you loose the heat from the 600 for 12 hrs??? This is my main concern for your grow op at this time besides,how many plants your gonna flower at 1 time and will they get the good light are you gonna have to shuffle around by trying to flower to many at 1 time.