Well its going to be close either way....unless you have a 12 year olds hands and a 9" dick.

A guys hands are more/less the same size. A dudes dick is going to be more/less the same size. And the whole width thing, unless you have some fat fingers or a skinny dick, its gonna be close.

All it is is proportion. A guy that is 5'1" isn't going to have size 14 shoes. A guy that is 6'5" isn't going to have size 8 shoes.