I've just attempted to fit an 18RGEU dizzy and ignitor etc to my 18RG and was wondering if you got yours sorted? The stock 18RGEU ignition does have a resistor also which I assume should be hooked up as normal ie ignition switch to +ve on resistor (also goes to ignitor for supply assumedly) -ve of resitor goes to +ve on coil where also there should be a start switch wire (or 2?)which gives direct battery conection during engine cranking. The -ve coil is connected to ignitor as well as tacho signal wire and air con (if you have it). And of course the two wires from the dizzy connect to the ignitor as explained previously.
I assume (hoping) this is correct and will be able to test as soon as my battery has enough charge to (hopefully) start my engine.