yunno, when i think of the full range of sounds that are heard in the spectrum of 'blues' - from stingin' thin tele all the way to very warm, barely any treble 'lucille' - i start to think that just about any pup can be played in a way that would make convincing blues ...
that said, i was gonna say custom custom instead of either custom or custom 5
i have a C5 and it sounds great for blues
good luck
t4d