You should make a bunch of these! Ive got one! 36x36x12
1/2" is a bit overkill for frag tanks, did you "run into" these sheets or buy em all?
I think a good size that makes the most of the acrylic is a 48x24x16, however a 36x36x12 has an extra square foot of footprint area, and can be lit well by a single 400w bulb, and its shallow for good light penetration.... pretty much the most perfect thing you can make out of a sheet of acrylic.