Hi Eamo,
Once it's all in the same program then there is no need. The easiest way to visualize this is to write a simple program with, say 2 operations with different datums and co-ordinate systems, then just select the second operation and go to solidverify, the remaining stock will automatically update taking into account the previous operations done on the original stock.
I'm not familiar with using solidcam for turning but for milling this applies. Test it out with a program is your best bet. Solidverify is excellent for exactly this sort of thing once you have accurately entered your initial stock values.
Rgds,
Noel.