The OAC ought to be a little easier than the OAP although with one arm pulls I haven't noticed any difference except right at the top where the OAP is much harder. But "Overhand" would be a pullup though...? palms facing away from you is a pullup.
I'm not sure how hard it is for 200+, that's what I'm trying to find out. For 260, I'm pretty sure that's damm good though.