Re: Carlton, Ford tone on a strat. .
It isn't the pickups, it isn't the guitars, it isn't the pedals, it isn't the amplifiers. It's fun tinkering with all that stuff and I do too but that's not really why those guys (Larry and Robben) sound the way they do.
Those guys (and EVH, Yngwie, EJ, SRV, Gilmore, Satch, etc.) sound the way they do because they are soulful, accomplished, master musicians playing in the styles they are drawn to play in and they have put countless hours in with their instruments - mostly out of the sheer love of making music. That's all there is to it.
As Jol Dantzig said: "Believe me when I say that some of the most amazing music in history was made on equipment that's not as good as what you own right now."
As far as putting humbuckers in a Strat goes I'd go with a vintage paf type pickup even though Robben has used a JB and 59n combo in some guitars. But I'd suggest Seth Lovers, Pearly Gates...maybe 59's. Or something even better from the Duncan Custom Shop.
But you'll never sound like Larry or Robben unless you have their chops, taste, soul, background and experience, because that's where that tone really comes from.
So instead of new pickups (or in addition to new pickups) maybe buy a couple of Robben's instructional DVD's and study hard.
http://www.amazon.com/Robben-Ford-The-Blues-Rhythm/dp/B0013XS88O
Everyone has their own way, and mine is to not even plug in when I practice at home. I plug in at band rehearsals and onstage. I write songs, learn new licks, learn new chords combinations, work on my technique, touch, vibrato, phrasing, etc.,
unplugged.
I don't copy anyone anymore.
I try to do everything in my own voice and I'm a firm believer in the idea that if I can't get a beautiful tone from my electric guitar playing unplugged, plugging it in isn't going to help. So I practice unplugged.