[ponokareefer]

I just did an upgrade to a 240 gallon, so went through some of the same questions as you are now. My tank is 96x24x24 with the back against the wall, so not the same setup as yours though.

I would go with 30 inches wide if you are going 20 inches high and going to be able to view it from 3 sides. You will be able to reach all spots in the system fairly easily, and with it being a peninsula style tank, your rock work will be limited as you won't really have a "back". If you go with a 24 inch wide tank, your rock work will be pretty "skinny", and your corals/anemones won't have far to got before they come close to the glass.

I would go with a coast to coast on the short end for the overflow. Everything that I read about center overflow's pointed to them being a major pain.

Have you considered Jebao pumps for flow? I picked up 2 for my tank and love the flow. You do get some noise that people have described as less than Vortech's though. For the price though, you can't beat them.