Whats the most effective method to resolve Zwift power meter calibration problems without sacrificing accuracy, and why do some users swear by the spindown method while others claim its a recipe for disaster? Is it possible that Zwifts own calibration protocol is flawed, or are users simply not following the recommended procedures? Should we be using third-party calibration tools, such as the ones offered by Quarq or SRM, to get a more accurate reading? And whats the deal with the zero offset issue that seems to plague so many Zwift users - is it a hardware problem, a software glitch, or just a matter of user error?