Very nice!
The main signal path is very similar circuit to mine except that mine doesn't have the third preamp stage and has a long tail inverter instead.
That power tube bias tremolo looks really cool too. Are you planning to build the reverb and tremolo?
If there is one mod I'd definitely recommend it's the master volume. Push/Pull 6v6s are plenty loud and you'll battle to get anything other than clean tones at home volume without one. I went with a Post Phase Inverter MV for mine because of the inverter but with the cathodyne phase inverter I think you can get away with the simpler pre-phase inverter. I'm sure that Rob Rob has plenty to say on the subject.