I've switched to a more aggressive hack of the IIsi MoBo by substituting the original soldertail PDS socket with a Wire-Wrap Socket that will join the Hacked SuperMac adapter to the Hacked SuperIIsi's Mobo permanently for the Basement PDS Card Hack. I've decided that going half-way using the "Machine Pin Hack" would be reversible, but less robust physically and therefore less reliable electrically.

The same holds true for the marginally less risky, but equally aggressive, removal of the NuBus Connector from my spare NuBus Adapter. The cut down Gemini Card (DuoDock Donation) will have its Male NuBus Connector replaced with a soldertail version as well, after this is fully tested in the unmodified NuBus Adapter's Slot, the NuBus Slot will be removed and the extra length pins on the wire wrap connector will be permanently soldered to the NuBus Adapter slot's pads.

Here is the simplified (I hope) diagram, showing how the Wire Wrap connector moves the Gemini Board & slots closer to the NuBus Adapter: