UPDATE: According to my watchsmith the gen spec gasket from Steve deosn't fit with my ARF 904L 2824 due to slightly different glas thickness between Prof and ARF crystal but the 2824 movement seems to be the same built and same superb quality like the one in the Fortis.
UPDATE: I am looking forward to receive my watch back tomorrow from my watchsmith with the new Prof 2xAR and after full-service maintance including nano sealing and various measurements.
According to evaluations of the high precision instruments both, the original ARF and the Prof 2xAR, resist up to 70m but no equivalent vacuum resistance (max. 50m). I am pretty impressed, though.
He again pointed out the very well built and precise movement of type ETA 2824 with very little imbalance.