PK works nicely in alder/maple neck-thru Jacksons - I have one in my KV2. I tune to Eb but you're going right down to B, so I don't think you'll have any problems with it being too bright.
Far from being "a mess", I find the PK has the mids you really need to get the best out of a Jackson. FWIW, clip
hereAs for Warpigs, I've never tried a CPig, but I'm certain the APig would work well - it sounded pretty damn good in my detuned Gibson (clip
here & in Davey's bolt-on Jackson, so between the two I speculate that it would do
"all out brutal" in anything :twisted:
Just to answer the quesiton of what
wouldn't work, IMHO the Miracle Man would be my last choice (not enough mids), followed by Cold Sweat. While I love the Holy Diver in Jacksons, it wouldn't be my first choice for tuning right down.
Nice Jackson BTW :D if I was putting a BKP in that I'd go for plain black open poled, possibly requesting black allen poles & slugs (if not a WP). Covers just don't look right in a Jackson to my eye, but if I did go for covers it would be black w/black allen poles. YMMV etc...