I do not believe that NGK has a copper plated core for their spark plugs. I think this is Champion marketing hype. I would use V-Power plugs, BKR6E-11(2756). I have heard that some bosch plugs do not work in certain engines? Have not seen this yet but usually go with manufacturers recommendations. Loved you lockout idea but would worry about increased cold pressure. Maybe a coolant bypass would be a good idea during the cold weather? Maybe using atf+4 synthetic fluid would help, Steven.