I use the california duster daily after I garage it & follow up with Optimum No Rinse in a spray botle as a quick detailer & MF towels on bee shit & bugs as needed. No pressure/rubbing. Wash it 5-6 times a year & garage it for Winter. Always looks clean -
I would be wary of using a duster and quick detailing the car. Any time you touch the surface you are risking marring. The less lubrication between the surface and the media, the more chances of scratching. I would just wash more often than doing those touch ups. It only takes 30-40 minutes to wash the M3.