The max size for a cruising couple depends in part on how the boat is set up. In other words, how easy is the boat to handle and sail.
On our Manta
42, all lines are led to a single electric winch
. The jib
is a self-tending, camber spar arrangement rather than a roller furling
. It tacks itself. There is a boom brake
and a vang standard.
If you are going to live aboard, then you want to consider YOUR needs, since guests will only be an occasional event. I wouldn't worry too much about how many people the boat will sleep at one time - rather, how comfortable will it be for you and your wife/companion. If it works for you, then your occasional guests will manage for the short term.
Hope this helps.