Hello, I am looking for a Wacom tablet for my MacBook Pro Retina running Mac OS and Windows 7 64-bit. The main uses are: 3D modelling under SolidWorks, Autodesk Inventor, 3DMax, Illustrator and Photoshop CS6 Mac version. I don't see any need to have a screen on the tablet. What is the ideal size? Any recommendation appreciated. Thanks.