These are all just opinions:
1. I don't know much about acrylic other than it's usually over-priced compared to glass. I know you're worried about weight, but if you can get a glass tank moved in, you shouldn't have to move it again anytime soon hopefully.
2. Shorter and longer is easier to clean.
3. I'm a big fan of bare-bottom with a painted bottom (outside of course) that looks like sand. I don't like having to worry about what's lurking in the substrate.
4. I'd stock at 10 gallons per discus bare minimum, and 12 if you can. Stress is real.
5. Clean your glass tank with regular chlorine bleach, let it sit, and then just rinse with water. The bleach will dissipate, and dose with Prime like normal to remove any residual bleach. The Prime removes any little bits of left-over bleach just like it would the chlorine from tap water. Just be sure to fully cycle your breeder after you use the chlorine, because it will kill any nitrifying bacteria.