If you really need redundancy, then use either the Sachse or the Silent Hektik alternator mounted ignition and retain whatever ignition you have in the beancan position. Both these ignitions are reliable (I use both on different bikes) have a variety of ignition maps, some of which are suitable for twin plug use, and being mounted on the crank will not be affected by any timing chain wear anomalies.
Changing over the ignition from one to the other can be done in minutes, I suppose you could make it switchable, but then sods law would result in having problems with the switch.
Both systems mount the advance retard electronics Outside the engine so they won't be subject to too many heat cycles, which I think was the problem with the Omega ignition sold a couple of years ago. Volker Sachse also sell a variety of ignitions for laverdas, Ducatis and moto guzzis, his operation has a low BMW profile, I came across him via an aussi Laverda site!