1) I designed new top plate chassis with a more spread-out design, but using the original transformers, tube rectifier and space for a new Tubesforhifi driver board.
2) New back plate ala Holger design with speaker binding post and test points for bias.
3) New front plate with Alps level control, on-off switch, triode-pentode switch and analog vu meter.
4) I will be reusing the SDS cap board I built for the old MK III. It will mount under the transformer using stand-offs. There is now lot of room.
5) I have a new, larger Edcor choke that will mount to the wood side with a ground wire going to a common ground buss.
So to summarize: I'm using original transformers and 6550's, original tube rectifier. I am incorporating the following mods, most from TubesForHifi: new driver board, pentode-triode mode with face mounted switch, bias trim pots with back panel mounted test points, new larger Edcor choke, all new tube sockets, new power cord, speaker post on back panel, vu meter, on-off switch and pentode-triode switch on front panel. That's all I can think of off the top of my head.
I am now assembling all of this, but I can't find Holger to help me though the wiring. I'm assuming that I wire the transformers as per the original schematic, correct? Bob Latino has a nice simple sticky on the triode-pentode mod, I think I can figure that one out, but I don't know how to wire the vu meter.