I think the C5 sounds best in a guitar like a Les Paul with a single cutaway because the single cutaway design shortens the neck and that combined with the thick mahogany/maple body makes for a guitar with strong bass and thick lower mids.
To my ears, lower mids and mids in general are what the C5 lacks a little of, so it sounds great in a guitar with plenty of lower mids.
In a double cutaway guitar with a long neck, like a Hamer Studio Custom (or double cutaway Les Paul, or PRS) you'll have have a guitar with less mids, less lower mids and less deep bass (at least compared to a single cutaway Les Paul) and in a guitar like that the C5 might sound like it's lacking midrange and perhaps sound "thin" in the mids and less pleasing to the ear...unless you're playing really loud.
Then the C5 rocks!