they're all different
Warpig: very heavy, alnico 5 magnet, fairly dark, organic sounding, over the top output...... etc. you know this because you have one.
MM: this is a tight Ceramic compressed sounding pickup, great for thrash. the name comes from a song by Zakk i think.
Nailbomb: Alnico 5 magnet, slightly dark like the Warpig, organic sounding, but not as much gain and apparently does good cleans. it is said here to be the most versatile BKP: from crystal cleans to heavy Death Metal.
Ceramic Warpig: because it uses a Ceramic magnet, it takes the Warpig, brightens it up and adds more bite, more gain and slightly more compressed. it is less organic sounding than the Warpig however.
i don't know about the PK, can someone add to this please?
i think you have chosen the right pickup for somewhere in between those bands that you mentioned: i love Zakk Wylde's tone and Soilwork's! Maybe the MM or CWP may be a thought for trying things out. they are better for a tight thrash sound, but will do ZW fine IMO.
hope this helps,
BM