The good thing about any stacked single coil i.e. hotrail, fastrack is with a little change in wiring you can split them to have the single and also humbucker tone.
To be honest their aint a better guitar than a strat with 3 rail pups, you have so many options available to you.
The strat players who post combo's not involving a rail are usually old style tone seekers.
Not that there is anything wrong with that, the older strat singles can be irish coffee personified, but you can get that today and also have the great chunky bucker sound.
For singles with rails I think Kent Armstrong pull the "vintage with bite sound" off better than most, for pure single demons you CANNOT beat Kinman pups.
Singles have always been a real clean pup, lot's of noise, but maybe in some way that brings out the warmer and also more "feel" orientated attributes.
Personally, if I still had a Strat I'd put a SD Hot Rails in the bridge, a Kinman Broadcaster in the mid and a Kent Cool strat in the neck.
This would on a Strat pretty much give you a Hot Bridge, Tele/Twang middle and Smooth neck.
I often talk bollocks though

And I also like Crow's tone on "Sting Me" so best talkin' to me about classic bucks/P90's and hot Tele bridge's!
Steve