At last my Get*Set*Go is finished! I was fortunate to get one of the last boards from Shannon Parks a couple years ago, and also grabbed one of the last pairs of James OPTs for this. I'm using a pair of NOS JAN 6B4G's, and I changed the power supply to use a 6BY5 damper diode.
The design calls for a 6AX5 rectifier which has a high voltage drop similar to a 5Y3, limiting the B+. However, I wanted to use an ST shaped rectifier, and found the 6BY5. This tube has lower voltage drop, like a 5V4, but needs more heater current. The Antek toroidal transformer is a good match here, giving just 300v with more current to the filament taps. When I breadboarded this my B+ at J7 was still a bit too high so I added a resistor before the filter choke and increased the RC resistors slightly. This gives me the target B+ and allows the circuit to run as it was designed.
I couldn't be happier with the sound, it's a great amp and worthwhile project. I hope one day Shannon will relaunch it along with his other DIY projects.