So ditch the cfls and just use hps's. You could use the cfls if you just lower the socket cords down to the canopy. If your plants grow fast you have to raise the cfls every other day.

Its funny the temps got so low after they were to hot. Its always one thing or the other. I remomend a thermostate, but because you like to DIY I bet you could build one.

Your the first person Ive seen build there own hood, congrats.