I pulled a Custom 5 out of my Edwards ES. It was a good pickup but it was a little hot for my tastes in terms of that guitar. It's smoother and less bright overall than the JB
Also, the low-end of the Custom 5 is big, but a lot, I mean A LOT tighter than that of the JB. The mids are more balanced/laid back in comparison, but it still splits great.
I janked the JB from my ESP Horizon NTII and put the Custom 5 there.
Regarding the Charvels, like
@Racerxrated already said, get a 2009-2010 MIJ (or USA if it fits the budget).
I got a Snow white 2010 MIJ So-Cal Pro Mod and the neck is great and that guitar plays great. I sorta made it my Adrian Smith guitar, as I initially got it when playing in a Maiden tribute.
At the time, these were delivered with a Tone Zone bridge (found it also a tad too flubby in the lows here, replaced it with a Norton) and an Evo Neck (quite nice actually, but I wanted a bit more thickness/smoothness, which the Air Norton delivered).
I can imagine that a JB will most likely be too flubby in the lows too *and* screechy up top (alder body, maple neck and FB....-->bright city), but that a Custom 5 will do wonders.