That's not the electronic ignition I was expecting to see. I have no idea who manufactures that system, or any way to diagnose possible problems. If I had the engine in my shop, I'd probably source a conventional distributor and coil for troubleshooting purposes and run a series of baseline road tests to see if the performance improves. The distributor housing is supposed to rotate counterclockwise a few degrees as the vacuum advance functions, but that will only happen at light load and relatively constant throttle. The dual carb setup might be dropping the vacuum enough to prevent the advance from working as designed. Is there any vacuum on the distributor tubing at idle? If the distributor tube happens to be connected to full manifold vacuum, it might be holding the distributor in the "full advance" position all the time.
Jerry