Micro-grow optimal distance to reduce stretch and possible heat burn

Babies have vegged a month now in flower and due to limited space want to reduce stretch as much as possible. 4 X 23W CFL in an old metal white box is my set-up, added another 27k to help with flower etc.. I know that 2in is the optimal distance from the light to reduce stretch while in flower but in such a small space I don't want to cook my girls (hopefully) what distance would be safe to keep them from the lights? I still have 6.5in give or take to play with. I know the box gets warm to the touch, with good ventilation, and I have read about uncontrollable PC grow temps damaging plant growth so I don't know to keep them close to the lights or bring them back down and cross fingers they don's stretch and get cooked anyway.
Keep them close to the lights or give them space to cool?

I had all my girls about 1 inch away with good ventalation, i used 4 23w at the beggining of flowering, they still stretched i say a good 2 inches but havent streched anymore other than the colas getting bigger. Juss keep your box at 70-85 degrees max