Mmm I've never heard of a dual point setup doing what you're describing Disston, but I do know that most Japanese bikes have this exact setup (Honda CB350 has two sets of points, independently adjustable on the valve cam). I guess a longer dwell time is a bonus, as there would then be no wasted spark.
Anyway.. I swapped my old advance in, tried indexing the advance to the left or right of the minimal slop caused by the flat on the cam, and no changes.
I'm doing it.. I'm getting a Sachse alternator-mounted electronic ignition. I like that it uses photo gates as opposed to Hall sensors, and I can keep my points in place to save headaches if it quits. Not as expensive as SH, easier to get than Omega. Just hope it's not my coils or timing chain causing the issues.. apparently there's no easy way to tell if the timing chain is worn on pre-canister models.