Nice tank if you look through one side and you can't see the other that good. If you can see just a bit that should be fine. If there are a ton of areas you can see through to the other side you need to add more. That is the best way to see. It helps if you don't place plants in a row or anything so that way you can make it seem more dense without it actually being so dense you can never see the girls lol.
I too am making a tank for a sorority the link is in my sig. I have live plants so I have to wait for them to grow before adding the girls. Hope this helps!