Looks like a cool project. I agree with those who say "why 470volts?" Even with the 6L6Gcs, (a pair of which which I'm trying to bias right now on my own bench), you need wiggle room, and 470 is so high that you won't have much...or any.
Cableing between top and bottom - I've built a few projects like that, and it sorta makes everything exponentially more tricky when pulling the amp in and out of the cabinet to tweak. I learned to use as much shielded cable as possible - particularly for signal lines of course; find a good quality 4-strand shielded cable, or 6 strand if needed.
I also learned to keep the on/off switch as far from the tone stack as possible. I ran two separate cables - one for AC power and one for the tone stack and controls. With good shielding, you can afford to add a little more length to the cables so that, when you pull the amp out to tweak on the bench, you don't have to also remove the controls and on/off switch. Instead, you can just lay the cabinet on its side on the bench and plug it into the chassis from there.
Did I say plug in? I should mention that I made the controls pluggable (is that a word?). I used shielded RCA plugs for signal. I connected the AC wiring using an octo-plug. This is something I learned from seeing how Hammond connected all the stuff in their organs - lotsa octo plugs. It may seem a bit low-brow compared to today's technology, but it works well and you can avoid noise issues fairly easily when done right. I feel confident you will want to have it plug-friendly once you start tweaking.
Good luck with the project.
Topic: Picking the Right Power Transformer (Read 10150 times)