Finally got the MegaSquirt fitted to the SD1. Once I'd finally got it to idle, the rest of the tuning to get it to run well was easy. Fine tuning for max power and economy will, I'm sure, take longer. What is immediately noticeable is how much more poke it has at low to middling revs - the old Lucas system was known for running weak there. Downside is the power doesn't come in with a bang at about 3500 rpm anymore. ;-)
I'm just using it for fuelling at the moment. Once I'm reasonably happy with that I'll change over to ignition as well.