I saw a really good post on how to fix your exact issue... Use a strip of egg rate along the back, notched out with all your devices, and then make the frames to fit the remaining space.
Tommy check the link i posted above. You can use eggcrate to create a straight edge to meet the screen top and cut out the eggcrate to fit around any equipment or plumbing.
When you do this, also be sure to add a piece of netting on top of the egg crate using small cable ties as many fish can easily jump through the egg crate sized openings
We demonstrated this at the swap this past fall.
It is also the same solution for bow front tanks -- by adding a piece of egg crate to the front