A few more pictures I found while digging for more information:
As often happens, Gillette was not alone in making injectors for twin blades. Both Persona and Schick made them as well in the same time frame, and they seem to have sunk into the murky depths of time without leaving much behind as well.
The Personna Injectore II:
The Schick Injector Twin:
I suspect the various twin blade injectors were plagued by the same fault as most multiblade carts; clogging between the blades...
All in all an interesting little oddity that I'm happy I stumbled across in my meandering trek across the internet.