My approach involves a pot spanner, screwdriver, wire snips and a bin...
Seriously though, just start unsoldering everything, starting with whatever is easiest to get at first. No point trying to work it out,.
Rewiring a guitar is dead easy.
OD in the loop increases volume up to the point where you're overdriving the valves, then it's just more distortion.
If youre having trouble being heard, try LESS gain and trimming back eq frequencies that overlap other instruments in the mix. What sounds great in isolation at home, rarely works...
Guessing you're in the UK. Good place for bits n pieces - pots, caps, screws, jackplates, etc - is AxesRUs.
Before throwing sheckles at pickups, as said, adjustment. Good starting point is neck 4mm under open strings, bridge 3mm. Tweek from there.
If you're going to get into changing...
I was actually coming back to edit my post.
As you're going through a mixer, an old recording/mixing 'trick' that might prove valuable is to set your sound up, in mono - no panning, better still, through one speaker. Tweek the eq, so you can distinguish between the two amps, they don't...
Different kind of stereo , here.
Been using a rackmount setup for nearly three decades, based around a Triaxis pre... Technically, it's just dual mono unless I use stereo effects.
Main thing to watch out for is phasing issues when using two speakers. Sound fine in one spot, but stand somewhere...
Aside from the durability, you're limited by the tolerances of the components. Hopefully, PCB parts use tighter tolerances than 'free range' parts. Point is, if a 500k pot is at bottom of spec, you can change it easily, not so much on a PCB.
Probably same as a Telecaster, just using different value pots and caps.
FWIW, I built a HSS Strat with stacked coil singles and SD 59, back in the 90s, with a master volume and tone. I just used 500k pots and a 0.022uF cap wired as per a Tele. Not excessively bright.