I bought a 4 inch tachometer for my stock wired 93 FD and I am wiring it to my ECU using the wire that comes off the stock harness that connects to the back of the standard gauge cluster.

My question is How many pulses per rev do I set it to and how exactly do I wire in the resistor to make it work?

I would assume just solder in one side of the resistor to the yellow wire and then solder the other side to the smaller gauged stock tach wire. Logically, this makes the most sense. If it were a normal piston engine it would be simpler but I am pretty new to the rotary engines. Thank you for your time and consideration.