Newbies first grow... any advice is good advice.

My first try growing, EVER. I bought DR300 although now I see that I could have gotten a much smaller tent but i was thinking of the future.Will that be a problem? Its a 9'10" x 9 '10" x 6'7, with ONE 3' x 6' tray holding 20 plants. 1000w bulbs with one small fan near the window to intake fresh air through the lamps and out of another corner. A large fan exhausting the tent air into a carbon filter. I have a portable A/C unit also exhausting and Co2 tank. How often is the Co2 supposed to be applied? I once read the smaller the space, the better it is due to humidity issues. Also any advice on my air venthilation system, odor issues, and lighting will be appreciated. And what am I supposed to do about the electricity since i am using 1000w lamps?

That's a very fine setup. You're going to see a noticeable spike in your electricity bill. Expect an easy $100 per month, maybe more(though I hope I'm wrong). Make sure you run the co2 when you can turn the exhaust off, like when the lights are off.

nice set up. looks like you will get a lot of budz out of a setup like that. good luck