I'm using an Omega and it works fine. As to the retiming after having worked on the alternator, I do it by markings on the Omega and the little magnetic trigger.
I can only recommend changing the whole electric system to modern units. I have a modern ignition coil, a combined rectifier and voltage regulator and the Omega. Apart from less wiring, the units are much smaller and works better than the old ones. The rectifier/regulator exploits the power from the old alternator far better than the old giving a charging voltage of 13.6 volts where the old never got above 13 volts. Charging begins at 1050 rpm, ie where the charge indicator lamp turns off.
Did I mention the smoother running of the engine?
greetings from a showery (thunderstorms) north