I've made a layout, but it's a 2 Channel amp with 2 different voicings, so a lot of switches (9 relais, 2 OptoMos), and smallish area 2 layer PCB.
You don't need to do it that complicated cloning PT-20 only.
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Transformers: power - custom toroidal, 260V AC secondary.
350V plate voltage, 330V screens
OPT - custom (self made) very big one! EI-96 core with 7600 Ohm Raa and 8/16 Ohm secondary