No hesitation: Catswhisker pickups.
I have pairs of their P90s wound within both Jazzmaster and humbucker form-factors. One fits a Fender J Mascis Jazzmaster (bought some years ago from David Martin) and the other (the HB) fits a Squier Jagmaster.
Excellent pickups.
The HB size is marketed in cream plastic as the Phat Moggie, or, as in the case of my Jagmaster, in white plastic as the White Pussy.
Website:
http://www.catswhiskerpickups.co.uk/Phat Moggies:
http://www.catswhiskerpickups.co.uk/p90.htmlWhite Pussies (on my Jagmaster): [url]https:////c1.staticflickr.com/5/4052/4629087517_05fa216840_m.jpg[/url]
The pickups are about £55 each (maybe a little more).