mtAl, first, a hearty welcome to Nitro Express!
Now, I have not owned a 9.3X72 but do have a 8X57R double and from what I have read on the 9.3, I would be inclined to look for the 8mm.
Seems like the 9.3 will run out of zoot at longer distances.
From what I have seen, the 9.3 is going to be easier to find a nice example of. In fact, there were a lot of drillings at the last show I went to for what I thought was reasonable money (compared to anything British anyway).