just to chime in on the subject, it's not all that related but i'm sure you'll see the parallel:
my upcoming BKP set is a riff raff neck and CS bridge. and i'm replacing what i had in my 7 string for a painkiller which matches up well with a mule. tim himself uses the PK-Mule combo and he assured me it balances out quite well :D
it's not 'cause they're at the extremes of the range that they don't match up
