My R1100GS manual states ignition timing is at TDC -- Motronic converts TDC value to 6° before TDC
My R1150GS manual states "Adjustment at TDC". The procedure isn't helpful, though. "Connect BMW MoDiTeC with adapter cable to Hall-effect gate plate. Set the timing, following the tester instructions." Right.
FWIW a search for .24 mm doesn't turn up anything. My manual is dated 02/00