Ok, I managed to acquire a reportedly working Space Duel board+AR2 set so I'm going to try to see if I can make this work.
I plan to use the current Asteroids Deluxe Power Supply Assembly, that has all the same voltages that Space Duel is expecting, but giving the correct voltage to the GO5 (60VAC).
Need to have the AR2 for Dual Space as well, since AD only uses 5VDC and SD is expecting 22VDC.
From the schematics, I mapped the voltages as follows
Asteroids Deluxe Voltage Map
Power Assembly to:
Monitor - 60VAC
Monitor - 6.1VAC (not sure what function this has)
AR2 - 10.3VDC
PCB - 36VAC ** DANGER TO SPACE DUEL PCB
AR2 to:
PCB - +5VDC
Space Duel Voltage Map
Power Assembly to:
Monitor - 50VAC
AR2 - 10.6VDC
AR2 - 36VAC
AR2 to:
PCB - +5VDC
PCB - +22VDC ** DANGER TO ASTEROIDS DELUXE PCB
PCB - -22VDC ** DANGER TO ASTEROIDS DELUXE PCB
As you can see from the mapping, care will have to be taken when switching from AD to SD.
I'll have to make some connector adapters to make this work with the AD harness.