Imo any cock above 5" should be more than enough, to make any women orgasm.
There is a lot more than just cock size to the full picture.
I'm 6.2" long with around 5.5" in girth and my wife has no problems in reaching multiple orgasms when we fuck, with toys or not.
Certain positions (like doggy) will make her uncomfortable with pain if I get all the way deep.
