IMO, you can do Slash with any number of pickups. He uses Duncan A2 Pros, so A2 Stormy Mondays are the obvious choice, but I really think it's easier to get a better sound out of A4 magnets (because A2 tends to have an annoyingly undefined, loose bass). A4, to my ears, keeps most of the benefits of A2 (mainly smooth treble), while having a more balanced EQ and more pleasant bass, so I find it easier to work with and more versatile (it definitely sounds better under more gain to me).