Crank Sensor
Here are some other ideas. It is possible to add tab and Hall sensor reference to standard distributor. It is possible to use a $1 microchip, and write simple program to decode flex plate, or distributor sensors, and make the output signal what you want.
I have done this to make engine management systems for various engines, retrofit PCM for different engines, make PCM test equipment and injector flow bench controlls. It involves using a timer to measure sensor edges, and state machine and timer abilities to generate desired logic outputs. Deleting every other pulse is trivial, however without reference sync, it will mess with fuel sync in MPI system, but work with bank fire.
I am not selling my service, but willing to help. I can often figure out what needs to be done and write code in a couple hours. Snap me a picture of the OEM distributor trigger wheel, and crank trigger if it exists. I am a bit confused with what year of PCM you have.