Davey, I'm another Davey, my grandmothers called me that my whole young life. In his instructions for Davis Diesel conversions Mr. Davis advocates running Diesels as near the peak as you can get away with and the compression just below the egg frying noise which I call the "secondary rattle". 25% castor is never going to allow the engine to be under lubed and when leaned too far Diesels don't go into the pre ignition mode, they just quit.