I have a box full of Schaller pickups, from many different brands of guitars. Schaller manufactured a *wide* variety of humbuckers, everything from low-output PAF style, to high-gain ceramic-magnet meatgrinders. Their PAF clones were really pretty good. Schaller had very good winding equipment in the 80's and 90's, as characteristically, most of their coils exhibit low capacitance, meaning they tend to cut bit less high frequency than comparably wound humbuckers from other makers. I have a Fender Esprit Elite with Schaller's most high-end pickup, also used on the Fender D'Aquisto jazz boxes from the early 80's MIJ "master series" (very nice instruments). Those are dark and highly overwound, but they are quite comparable to the SD '59 neck and JB Bridge combo, though constructed somewhat differently and with coil splitting.
Can't really pin Schaller pickups to any one particular sound. They made an enormous variety of pickups, usually to whatever the OEM guitar manufacturer ordered. Schaller wasn't really available in the retail market for the most part. They'd probably still be around had they gotten into that racket.
I mostly play blues and rock on the 535 with the HRW's. I find they work really well for that, and I can dial in very good tones with same tube amps I've been playing for decades now. Playing A/B side by side with a Collings I35LC and the Throbak SLE-101 Plus, they really were very similar in the H535 vs the Collings.
On the other hand, I find the SD59's that came stock in my H150 to be higher output and darker, with a frequency response peak that sits a little lower in sort of a strident range.
to each his own I guess. Changing pickups has become like changing socks these days. In the 1980's, it was kind of an exception to the rule, as pickups weren't quite as readily available on the retail market to players. Dimarzio and Seymour Duncan were kind of the early players in that market.