hi. i never liked the little 59 or jb jr, real humbuckers sounds better. i had the hot rails in the bridge of my 57 ri for many years and i loved it ,a real beast of a pickup for solos . i swapped it for the seymour stra bro 90(custom shop ) it's a single coil sized p 90, sounds thicker and darker than the mini humbuckers and i love it. i also recommend adding a tele option bridge+neck great for cleans and drive ,but don't bother with all 3 together it sounds weird.
Id go without pick ups begore id put any seymor duncan crap on my guitar.HE HAS NOTHING TO DO WITH THIS COMPANY.SOO MANY MORE PICK UP WINDERS OUT THERE....SORRY MAN.