Here is one of the 24 bits of the instruction register.
3 relays each amount to 72 relays.
The instruction bus uses 6V signaling to provide more swing into the capacitor, but not enough to damage the diodes (the KOA diode networks are limited to 7V in reverse polarity).
The sensor is made more sensitive by charging the capacitor with a higher voltage swing, bringing more charge to upset the coils. The middle point is centered by resistors, but large capacitors are required to keep the ends at a somewhat constant voltage. I got a stock of 1500µ capacitors so the swing ratio is at least 1/10.
The reduction of the current on the instruction bus is pretty important. If 60mA per bit was required, then a INV instruction (FFFFFFh) would draw 1.5A ! Hopefully this is now reduced to about 10mA, or 240mA for a full FFFFFFh instruction. This increases the longevity of the parts...
I'll have to prototype the above circuit !