I have had the priveledge to meet one of these people you guys have been so quick to crucify and trust me lesley ann dimmer is not greedy ,stupidor taking advantage of even tax exemptions she is total opposite of what u or the news or the feds are saying she let me share her last cigg with me...
the answer is how many plants you can put in a 17ft square area, depends on how big they are and what size containers there in.it could be a 100 tiny plants in small containers or a couple big plants in big containers depends on your preference.as for how far above the plants should they be hung...
not sure i know u breath out co2 and take in oxygen and your plants take in co2 and make oxygen so it would make sense that it would come on less with you in there then with the plants but honestly i dont know for sure sorry couldnt help more