It'd have to be closed to prevent any light leaks...Having light on the plants during lights out will confuse them and cause them to hermie.
And from what I've seen and read 18/6 seems to be the ideal light cycle for auto...But keep in mind I've never grown autos, so take this with a grain of...
Prime temp would be around 70F - 73F...You will need to keep the door closed during their dark time, and it'll probably be a pain in the ass to have to close the door when the lights off and to open it when they turn on...And what about when you're out of the house for majority of the day?
Yup, I'd take it back, the spectrum of light it emits is horrible, the lumens per watt is extremely low...Those things get hot as hell too, most of the energy is wasted as heat! You'd be much better off with a 250w HPS
Right at the tops of the plants is where the gauge should be...And it would be wise to try and keep the temps in that area under 90 degrees F, 95F or higher and they will die.
They should be around 12 inches away from the tops of your plants.
Exhausting your room will definitely take care of temps...How about buying a cheap door at a hardware store that you can cut into and run the exhaust from.
Really nice cabs you got there stoney!!! I wish I had that much room to work with! I really want to go perpetual, not every week though...It's really hard to get that shit dialed in, ya know!
Anyways, my girls are lookin' nice and healthy, they're about 12" tall so I'm gonna give em' about...
Actually, the upkeep doesn't cost much at all...A 250watt light will only cost about $20 a month in electricity. And that's here on Guam, where gas prices are $4.65/gal