I am building a 55gal but am stuck on the vent. How should I, in your opinion, arrange the vents? One on either end? across the entire front? entire back? Thinking I'd do 1 1/2" -1 3/4" if they were on the ends and prob only about 1" if across front or back? I was thinking front to help keep glass clear, but then I got to thinking about how to attach in the back or if to attach in the back. I'm kind of looking for as large an opening as possible for ease to work inside. I've seen a few, but how many people would not attach the glass on top at all? Just use a solid piece and gravity, been trying to devise some sort of clip to hold it down. What do you guys think?