#1- Nice grow tent, how do you like it? I just got this one (
CLICK HERE) in the mail and havnt evan had a chance to set it up yet.
#2 looks like you could use a little more air circulation (1 or 2 good size oscillating fans), does it seem to filter out the old air pretty well!?
#3 The plants hight should be fine, they shoudl not get much bigger, they will get a little bigger but not to high with that tent. the only other thing i ntice is you might be crowding them a little, but if its made it this far and looks that good, DONT TOUCH EM, they will do fine!
#4 yea gringos right, when the co2 comes on, all fans need to go off. You want the plants to soak in most, if not all, the co2 within the tent. Then when the co2 goes off kick the fans back on about 5-10mins after the co2 goes off, give the plants to a little time to soak the rest of the co2 out of the air. You should have all this set up on timers. Another good thing is club soda (no sugar) in a spray bottle, and just spray the plants . Good source of oxygen for the plants!
Good luck and hope everything goes well. Hit me up if you got any more questions, Im happy to help!