Here is a little mod that i did on my six million$man to help take the stress off the ground return line connector pins back to the power supply. I just run a few wires from some of the SCR ground traces back to a crimp connector that screws under one of the board mounting screws and gets grounded to the backbox aluminium ground shield.  This worked well on 6m$m, making the lamps brighter so i thought id do the same for KISS 

And a pic of the boards all installed in the backbox