Honestly to cover the whole 4x4 is recommend 4 300w Mars, but two will get you started and you can suggests move up! Good idea on the CD case thing. I used to just cut plastic waters bottles in half and use both pieces as domes until I found these nifty little things!!! LolI do this same way works like a charm I tried the paper towel to much handling for my nerves I love my hps and went with it because I still am not comfortable with led which I'd love to have to get the ones that work good out of my price bracket and like you I do t know if that kind of investment will pay off for me so I decided to flower with hps and veg with led I'm in process of moving new home new set up in a 4x4 custom made box itself 6 ft tall I will only be vegging how many Mars 300 old their panels do I need I was thinking two smaller ones instead of one big one? I'm always meaning to get clear cups for humidity domes somehow they are always blue or red they bring in I broke down and took all my cd covers off they work great and can reuse many times then put up.
