Custom building a sump

[Eyford01]

Hi everybody! I'm looking to add a sump to my 55g and I have nowhere to hide it so I was thinking of having a large standing column if water right next to the tank, I was thinking 12" x 12" by 48" tall to make about 30g, I realize this is a very unusual size and shape but I have it planned out and I think it would look pretty cool, however my problem is what material to use glass or acrylic and what thickness I need, all info i've found says depth is the deciding factor for thickness but if it's 12" x 12" will I be able to safely get away with thinner material than the charts on the net, cost is important at the moment unfortunately and I'm considering just using a plastic tote as a temporary stand in, any suggestions are appreciated thanks!