Buying the 16 foot leash did the trick. He's got enough separation from us that he's getting the job done. We've had one accident in the apartment... when I slept in yesterday and he couldn't wait. I'm not going to do that again.
There's a certain area of the apartment complex he seems to like for getting the deed done. I don't care really, I'm just glad he's finally going normally.
I still can't find the flush handle.