What is important is the current through the points. I don't believe that resistor has anything to do with oil filled coils or not.
The condenser has to be the right size, not bigger. The Motors manuals of the fifties have a good description of determining the correct size based on which of the points contacts is cratering. The condensor absorbs the energy in the primnary of the coil when the points are opened (the current in an inductor cannot change instantaneously). Since the secondary is not perfectly coupled to the primary, there is still enough energy in the secondary to fire the plug.
