Man, first somebody looking for Garcia tone, now this ....
How would an Abraxas in the bridge and an Emerald in the neck sound? I am in the planning stage of building a Warmoth guitar, and it will be a Koa Semi-hollowbody with coil taps. I'd like a warm Sanatana lead tone with enough mids to stay bright and crunchy when I roll off the gain. Thanks.
Welcome to BKP, jam-loving brothers! :) Anyway ....
For Santana tones: Abraxas. 'Nuff said! As for Trey, he uses Schaller Golden 50 pickups, which as I understand it are supposed to be very PAF-like (~8.2k in the bridge and ~7.4k in the neck, I believe). I'd not hesitate to pick the Mule as an appropriate BKP here.
Honestly, I think you'd probably be good going with with either a Mule set or Abraxas set. The Abraxas is, as I understand it, voiced much like the Mule, only hotter than a true PAF-style. It's like a "Mule+". For another, option: If I recall aright, Trey uses the neck pup a lot for cleaner sounds, so you could put an Abraxas in the bridge and a Mule in the neck.
Either way, I think a Mule or Abraxas in the neck will get you closer to where you want to go than an Emerald in the neck.
When I was choosing pups for my LP, Trey and Santana tones were two of my major touchstones. I also wanted the ability to take my sound up into a more metal zone, doing Iommi and Kyuss and Roy Z kind of tones, so I went with a Crawler set. A Crawler neck is actually the same as an Abraxas neck (and I
need those Santana neck tones!), but the bridge has a bit more grunt and midrange; it's got vintage vibe but is moving a bit further of that feel than the Abraxas. But if I were Trey, I'd get Mules; if I were Santana, I'd get Abraxases. I think a set of either or a combo of these is what I'd consider in your case.