If you run the "smaller" pad for dozens of track days, wear down a lot of the disc, then switch to a bigger one, you'll have an issue with the pad dragging and wearing unusually.
If the wear difference (height?) is a few MM, that's when I would be leery. 1 or 2mm more rotor material around the outer edge will wear away without much of a problem, IME.
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Now: 2017 Corvette Grand Sport, 2021 AMG C63 S sedan
Past: 2011.5 M3 sedan ZCP
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