L3n4rd,
A 9.3 based on the .375 H&H Flanged would have a head diameter of around .502" and case lenhth of around 2.94". The length is not much different,but the head diameter is considerably larger than the 9.3x74R case.As far as x72R S&S vs x74R cases are concerned, I would only consider the x74R cases.They are much more common(therefore cheaper)than the x72R S&S case and the casehead is not enough smaller to make any practical difference in fireforming.
Mike