Proof that tube-amplifiers are not rocket-science. It's the crudest form of electronics possible; just follow the layout and pull the switch.
Every second spent fiddling in amplifiers is time lost not making music!
That is your point of view and it is of course OK. But better get someone doing the job for you if you want to keep on playing guitar on earth and not somewhere else.
It is not only follow the layout and pull the switch as you can see.
Best regards, Dirk