I'm in the middle of the mods.
First round, I did the most rewarded combination of C3,C5,C6,R15,R21,C15 (according to my synthesis of this forum thread)
The amp has less highs now, but EQ is more controllable.
I need to try it out during the rehearsals tomorrow where it is cranked up and input signal boosted by my GT-5 pedal board. I was planning to do the R39 mod, but I don't know which channels it impacts. If this allows to crank up the clean channel and controlling the master volume with it (potmeter), than this might produce an even rounder overdrive.
I'm working in the direction of the Fender 5E3 sound (which never will succeed completely). But this amp fits in my budget to use it for lead guitar in a Neil Young tribute band.
A side project will be the control of the pot meters with servo motors. My Boss GT-5 is a versatile and robust beast that has some nice MIDI features. Those midi messages will be taken in by an Arduino and this will control servo motors which will drive the potmeters.
This will allow me to tweak the sound from soft and harder rhythm parts to a "full howling drive with delay" lead sound for solos.
I can use 5 patches and the express pedal to program whatever I want 😉
I'll just keep this posted here. It always can add more context to the splendid information already available here.
BTW I always play in triode mode.