Hey would both do the job but you want to be useing these when the plants are ready to be flowered .you can flower a plant has soon has it has legs but i would advise on waiting till the plant is at least 1 ft to 1 and harf foot the bigger the veg then the larger the yeiled.but try to get more tighter internodes than a bigger plant get them lights has close has possible inces away.have the fans blowing up onto the light and this will aid the cooling of the room.you could do with getting a exaust fan too to get rid of the spent air you want nice fresh air in the room instead of stagnent.if money is an issue buy one that is used in bathrooms or even better the ones used in kitchens you can just add a plug a these are a great little tool untill you have a better one you can buy cable exaust fan for around £20.