Just run everything on 12/12.
Get your head out of your ass
And educate yourself before you start something...
I mean dude..or girl...you are making every mistake you can make that you shouldn't even make if you would read a bit first how the cycle goes etc.
Just put all your plants in the tent with the 600w and put the light on a timer 12/12 and stop stress and do something that is reliable for once.
Stop messing around with 40w grow lights, no wonder they stretch..if you keep going at this rate with your mistakes, you will not even get 4 oz with your 600w..
So all plants on 12/12 and do what i say or other say, because you have no clue how to go about it.
Try to at least run this grow to the finish if you even can make it that far.
Your next mistakes you prolly will make =
Overwatering or underwatering
And problems in the nutrients area, i do expect leaf problems to show up and that you have no clue what to do, how they came to be and how hard they affect your yield.
My best advice in your situation is, to use this grow a a learning process, and don't focus too much on yield, but focus on being able to keep the plants alive till they ready for harvest.
Sry but i have to be though and strict..unless you want to fck up your next grow too and the grow after.
it doesn't matter if you have 600w or 1000w lamps if you don't have the fundamentals under control, even a guy with 250w is gonna yield more then you with 600w