What you need to decide is if you want a Luminor or a Radiomir. If this is your first Panerai, I would suggest the a Luminor since I consider the Luminor case to have more Panerai essence.
If you want a Radiomir which will fit comfortably on your 6.3" wrist, then the 42mm PAM338 titanium Radiomir w/ the in-house P.999 movement is a perfect choice.
You can't go wrong with either. Just make the decision on which case style you want.
Please do keep us updated with your decision!
Cheers,
Anthony