I've never encountered the dreaded squeal but it could be due to the close proximity of the wires in the cable entry. You can try adding some heatshrink to them to see if it makes any difference.
Good move as I really don't have fond memories of my old BH arriving with the BG's pushed into the chassis... \
What color did you choose my crazy elephant friend?
If both amps use the same rail voltages and the PSU can cope with the load I see no reason why you can't use a single PSU to power both amp sections, one at a time. The loop out is just another set of sockets wired in parallel.
It's not that bad really, a little charring on the finger and I'm still a bit numb but that's about it. What I'm angry about is not realizing that the B+ would also be on the delay relay terminals...
Woke up, went to work, got home early to work on some of my amps. While setting up a PSU I accidentally zapped my thumb with 350+v. There is a burn mark and everything and I still haven't tested the PSU. Here's hoping I won't be zapped again...