I think it’s quite common to fit a single bailer, but as you suggest it could be tricky to get access to it from the ‘wrong’ side. Mind you, you can’t normaly reach the bailers without bringing the boat level anyway. I usually wait till going through a tack before opening or closing them.
I have to admit on my (previous) twin-bailer boat I never actually got swamped and so have never tested whether a single bailer would be up to the job or not. These days I sail a World which has two big transom drains plus two larger bailers so there are no problems in that department!