I actualy just got done rebuilding a 90g tank
foot print 48x18x24

glass thickness is 1/2" I used black silicone on mine

biggest thing to remember is when you build it have your tape ready to hold the panels up and that your work table is large enough to hold it all

also don't try and move it once you put it together for at least a day or two as to make sure the silicone has a chance to fully cure

do your panel edges let them all cure good then go through and do at least a 1/2" wide bead down all corners smooth quickly so that it tapers out evenly to both sides the bigger the seam the stronger it will be but if you go to big the silicone will not cure

bout all the tips i can give for now if you Google tank building you will find a lot of info and probably a calculator that will give you the dimensions for your panels and glass thickness