Re: H-S-H Strat: Split humbuckers?
SSL-1 is good for middle, depending on how hot you want it. I agree with Stag Mag at the neck. There's no stock Duncan that I'd use at the bridge, but the JB or Distortion are probably the best choices. I've always preferred the changes when I put actual alnico5 polepieces in the "splitted" coil of the bridge bucker. I don't know if that's possible on the JB; Duncan makes these nice & tight. You can't use the screw side for this unless you ream the holes bigger, and getting slugs out would take some work.
Other options are Rio Grande Muy Grandes or Tallboys, or roll your own as I mention above. My next project is mounting an actual single coil pup (tele-ish, maybe a twangbanger) to a bucker plate along with a coil & mag from a bucker. You don't get more single coil-y than that. ;-)