sure..you can continue to LST during flowering just be careful. Another thing that might work good for you is supercropping. I can't bring myself to try it yet but people who use the technique sware by it. Not sure if there is an article on the site about it. If you need more info let me know and I will do my best to get some up for you. As for the fans, they can be pretty noisy unless you insulate them. I used foam...the kind you use for floating floor underlayment, folded up into several layers between the mounting bracket and the 2x4 that it is mounted to to help keep down vibration, but you can find info in the diy section about how to build a insulated box around it to help reduce noise if that is a problem as for the size of the fan, I'm not sure if it is enough since I don't actually know the dememtions of your grow area. To calculate the size you need, you need to figure the cubic footage of your grow space. Your fan needs to be able to move the air in the area to relpace it once every 5 minutes to be affective. so a 100cfm will take care of a 500 cubic foot space.