looking at my 4 ft 90g it has 1/2inch glass
looking at my 3 ft 40b it has 1/4inch glass
both of these tanks are manufactured tanks not home built like your doing but should give you a idea for glass thickness .
maybe this chart can help you
Calculate Aquarium Glass Thickness - Custom tanks are great investments | Aquarium Tools
looking at your dimensions I have a couple of questions .
46 inch long did you know your 2 inch shy of 4ft?
17 inch wide why a odd number ? why so narrow ? to give yourself some room I'd do 24inch wide
22 inch high.
I'm also going to assume your building your own stand
please post your progress of your build once you begin your build