Ok, there is no really easy way, but on my escort dizzy, I removed all of its internals, and welded up the shaft (so that there was no vacuum or mechanical advance any more.
Next I bought a Holden Camira Distributer (I assume you are in AUS here, given we are talking about a gemini)
Take the internals of that camira and graft them into the gemini dizzy.
You need to take off all teeth on the camira disc, except for one. This will become your sync sensor.
Next, buy a 12 tooth chopper disc from motec, and mount it to the front of your engine, like this.
- cranktrig.jpg (54.68 KiB) Viewed 7079 times
Use a GT101 to read the sensor mounted as you see in the picture.
This will give you a good reliable ref and sync setup for your car so that you can run sequential injection and even 4 individual coils as well.
There are some other options to run group fire and alike, but this isnt too difficult, and will give you the best outcome.
-Jamie