I have the Butler Creek covers. They fit perfectly.
However, if you really plan to bushwack with them, flip-ups are far from perfect. Here in chaparral country, I ended up flipping the things open on twigs more times than I can count. I'm not sure if they're worth using in brush, since they hardly protected the lenses when they were open at the worst times!
See-thru covers with rubber bands might be better. Just plan on sacrificing them now and then, and buying new ones. I don't know. Anyone else have something that works?