If youre going to pair it with a Blackdog i think the Mule AIV neck wont be too thick, actually i think it will be perfect.
Anyway i think you should just get the Mule set, youve suffered ULTIMATE TONE DEPRIVATION for long enough now :lol:
EDIT: An alnico II SM will be less bright then an alnico IV SM, so if the II SM is overly bright when paired with a Blackdog (and i can imagine it is) then a IV SM will be even more so i think....
Jus remembered something, ive heard about the combo of AIV neck and AV bridge supposed to sound really awsome in the middle position by the way.