I would do a 265 on an 8.5 wide tire, if a 255/35 works then a 265/35 is just fine as well.
A 255 on an 8 wide gives some rim lip protection so a 265 on an 8.5 wide will help as well, you dont want to curb those nice wheels do you? Plus you always want a nice flat sidewall on your rim or it looks all stretched and bad.