With any of those overflows you have 3 pipes going down to your sump. To allow for later easier plumbing changes you could install a union on each pipe at some point that makes sense to you and the design you come up with. Your plumbing is going to depend on a couple things where you install your overflow, the size and placment of your sump, the design of the sump, and of course the height of the stand. Same goes for return pump I would also put a ball valve on either side of the return pump one on the sump side and one after the pump. Unions for each side will help also if you have to change out the pump.











