Lol these questions are so loaded. Any answer other than "I prefer Average to below average in size" or "size doesn't matter" gets attacked by all of the guys on this site. Face it guys, you don't really want to hear our opinions as you're never satisfied with the answers you want, and you're horribly offended by the answers you don't want.
elephant trunk. jk. no preference, just as long as it isn't a micropenis.
I'd expect him to be like 2 feet long, Any less than that is unacceptable.