multielectrode plugs are only good if you have a very very capable super low impedance ignition coil on the engine.
otherwise the intensity of the spark on the multielectrode plug will be weak and you wont have proper flame speed - adding advance will just decrease the power more.. If you have a bone standard engine running bone standard compression use standard copper core plugs which last for about 12K kms easily..
make sure that you are running best ignition timing i.e. if your car is a carby be sure to check the centrifugal advance in the dissy - if its fully electronic or DLI or just EFI with dissy - you wont have the centrifugal mechanism.