Stopped trying to polish a turd. Realized that everything in the signal chain had to support the tone I was looking for. I wanted JCM 800/Plexi tones and most of the amps I had were Fender voiced circuits - close but no cigar. 'Polishing' with pedals got me only part way there. Bought a JCM 800.
I built a 6G3 Brown Deluxe clone that was greatly improved when I changed out the stock 16/16/16/8 filter bank with 40/40/40/16. Added girth and bottom end punch that the stock power supply lacked.
And this '64 Bandmaster went from good to great with the addition of an RCA 7025 in V2 and a pair of =C= 6L6's biased warm.
My current amps are pretty much bone stock handwired tweeds, so short of messing with amps I think are already great, I went and bought proper covers for transporting them from home to jam to gig and back.
Left it alone and just played better through it. I'm done with endless tube and speaker swaps. That malarky has never lead me anywhere but to confusion.