im and inch taller than you and i got the ar6 181 center mounted and they are fine. not too big at all, and you dont really notice the difference. however if you are going to be skiing bumps i found it a lot harder with the longer tail! but on groomers and in the park no problem.. hell of a lot of fun!
something in the 170 range would work im 5' 8 and on 171's centered.