I then drilled some 1.5" holes on the back of the tank for 3/4" bulkheads for my closed-loop filtration system. I drilled them a little oversized and then gave them 4-5 coatings of epoxy. They are still a little bit bigger than the bulkheads need so I ended up back-filling them with silicone when I installed the bulkheads to make absolutely sure I get no leaks.
The bottom of the green tape on the back is approximately where the water level will be. The two holes on the right hand side of the pic are for drainage and the one on the left is for the submerged return. There are two more at the top left corner which will feed the dripwall returns but they aren't visible in the pic. The other hole that's slightly higher up on the right hand side will ultimately be connected to a fogger/humidifier.
I then went ahead and put in the glass! I'm using a 3/8" piece for the side window and a 1/2" piece for the front (both of which I ordered from Glass Cages). I installed each pane by pressing it in horizontally and then tipping the tank so the glass was facing down. I stacked a big pile books on top for weight. I only kept the weight on the glass for about 24hrs and then turned the tank back upright - I hope that was enough time. I used a lot of silicone (about 2 full tubes of GE-I per pane) which resulted in a bunch that was squeezed out and had to be cleaned up later. The seal looks pretty good.