Was the CX carb a Weber or a differently jetted Solex CIC? Carburettors can be really rewarding to work on and it sounds like the hours you invested paid off in the end! :-)
I also considered EFI at some point. The arduino project looks really interesting! The starting point for my project was however that I wanted to keep the original Bosch distributor (and my Weber DCOEs) but wanted to be able to verify the actual curve - and eventually tune it by exchanging springs and weights inside. For that I needed a device that would allow me to measure advance while the car is running on road or rolling road. 
					
				