If going one size up bothers you for whatever reason, then keep it stock size (245/35 R19 (F) + 265/35 R19 (R)). It's perfectly OK.
FWIW: here's the setup on my M2C (and IMHO fit for purpose for my use) (no rubbing - no iDrive error messages):
Fresh rubber - Front (PS4S - 255/35 R19):
Fresh rubber - Rear (PS4S - 275/35 R19):
Recently at night somewhere on a calm German Autobahn:
