I suggest you to read first this thread:
10mm Reloading Forum > Accurate Arms Data
and probably you will get a lot of information to start loading with AA #7 which is one of the most recommended gunpowders for 10mm. With AA #7 you can even try with CCI 350 magnum primers, but start 10% lower with magnum primers than with regular. And carefully observe brass and primers for any overpressure signs at every shot.
If you have never loaded 10mm before, you MUST read also this thread:
10mm Reloading Forum > All Forum Users Must Read This
Enjoy your 10mm and stay safe!