The settings are available--they're just locked up in his Shellac head.
Maybe someday someone will open like it, like one of the pyramids, and divine the secrets.
I think Steve's tone over the years was always greater than the sum of its parts, and the gear aspects of it meant less as time went on. I saw Shellac do an in-store at Reckless in 2019 and they didn't bring the Shellac amps. Steve just used a blonde Bassman with a 4x12" and guess what, it sounded exactly like Steve.
Yes.
I heard him play acoustic on several occasions, and it sounded exactly as you would expect. Always funny.
The pick mattered--just using a metal one can get you some of the "skeeeeeeng" sound, and the notch does this funny doubling effect.
The out-of-phase neck/bridge thing in BBlack, the full-range cab thing...all part of it. Solid-state element in the amp part also, throughout.
But I know he would use literally whatever amp was around on the Shellac records, much of the time, and it didn't sound markedly different. The TB500 was more or less a constant as far as i know.
The Percolator was critical in that it could play itself, and when whatever needed to happen was beyond his ability to play it, he'd step on the Perc.
It's like the way Hendrix or Pete Cosey used the wah pedal. I don't know if you've ever used a wah pedal, but they're essentially useless for non-polite playing unless you do what they did and really whack out the signal in another way, either going into the pedal (for sure Pete Cosey, heavy fuzz) or on the amp side (probably more Hendrix), in which case the wah can get really vicious.
Or when Richard Lloyd would wind down his low E string until he could pull it behind the neck like the string on an archery bow--one of those moves to get beyond the regular guitar stuff.
From a playing standpoint, his willingness to utterly abuse his equipment was higher than most people, and he had big hands. He played a lot of surprisingly weird, spread-out chordal stuff in Shellac in particular.
I think he considered himself to be somewhat lazy as a guitarist, shortest distance between two points kind of thing. But his idea of obvious was not a normal person's idea of obvious. He would make connections, between fairly mundane mechanical parts (re equipment), between musical/sonic notions, that seemed normal to him but were definitely super idiosyncratic.