From what i read abotu rimless, it's prob best for smaller tanks. You have to keep it balances so it has equal pressure on all corners. Has to be very thick glass/acrylic because thats the bonding edge that is holding the sides together (i think it should be rather easy to do with acrylic as there are some really good bonding agents like weldon-4 to weld the edges together). Need a foam pad (well a lot of people use it to help keep the balance??). Rimless is sweet, but without a way to make a really solid seam, i dont know if glass would be my suggestion. Acrylic, sure, as long as its thick enough and had a really strong weld. I prob wouldnt use anything less than 1/2-2/4" thick on that size of a tank so that 5 years later it doesnt split.