if you're talking the bridge pickup, you'll need a 4mm magnet
the neck version is 3mm
I don't think this will brighten things up
the cold sweats are already quite bright
perhaps you should consider another set (rebel yell bridge/holy diver neck, for example), or something less hot, like a riff riff set
the neck cold sweat sounds pretty good in the bridge position, by the way, and much brighter than the bridge model in a good way
very very paul gilbertish
if you don't mind the shorter pole spacing, I highly recommend you try that first