Nice video but I though you would put in a bit more 'pride' and nit picking into the layout and make it a bit nicer/teach the young ones some tricks.
Why not:
-use (almost) the same fanout on each tube
-set up proper design rules/classes for the high voltage stuff. Everything 8/8 but the HV stuff 15/15 for example.
-tidy up the schematic
-tidy up the silkscreen
-use proper 3D footprints for the IC's (Altium IPC wizards even generates those) and the module
-'direct connect' and don't use thermal relieves on via's and tent those while you are at it
I mean, it is a functional board but why not teach the new kids something more than just maken a functional board.
Like you said, pcb design is an art and it's ok to put a bit of effort and pride into it
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edit: I know it's a one off board but this video will be watch by >100000 people.