“but no distributor that I am aware of was designed to operate such that the timing was retarded when the engine was accelerated.”
MOST vacuum systems were designed this way as most use manifold vacuum…Some used “ported vacuum”, taken from a carburetor port that only delivered vacuum at part-throttle (cruising).
This retards the ignition advance during acceleration to prevent spark knock and detonation…The centrifugal advance, a separate system, is sensitive only to RPM and it provides all the spark advance an engine needs under acceleration…When cruising along at high manifold vacuum, the vacuum advance adds more advance to provide good fuel economy. But this “full advance” (centrifugal + vacuum) could not be tolerated when accelerating under low or no manifold vacuum…