At first glance, I've had the best results with amp-simulator.pd above.
I added a wet/dry mixer to it, took out the EQ and spring verb, and I can get a huge range of sound qualities out of it, but things like keeping levels consistent relative to the source material aren't necessarily intuitive, and there are combinations of settings that look very different from each other but sound very similar.
I'd classify these sound qualities I can get out of it along a continuum ('less distored' to 'more distorted'?) that doesn't necessarily correspond directly to single parameter changes. I really want to be able to assign a knob or two on my control surface such that each one varies multiple parameters as I turn it, so the output can sound more distorted without my having to, for example, reduce the 'gain' setting on the compressor as I feed hotter input to increase the distortion effect.
So maybe I'd have a knob to control "brightness" as I perceive it... and maybe one to control "grunginess"... I to be able to intuitively change sounds on a dime in performance.
To restate/clarify, I love the range of sounds that this thing can produce, but it's counter-intuitive to operate, and I want to improve that aspect of it. Any help? Anyone dealt with this before?