I've set up an extremely simple AutoHotkey script for left-handed tablet users. It assigns each of the nine main brush tools to their corresponding locations on the number pad. Enter is assigned to Shift, to allows for tool inversion when held with left-click and panning with middle-click. Plus/minus zooms and period toggles wireframe. It's pretty self-explanatory.
To use, paste into notepad and save it as "Sculptris.ahk" - with the quotes. You will need AHK installed.
The resulting Wacom stylus configuration I find most effective is Alt for the lower button, middle-click for the top. Not sure if there are any other left-handed users out there at present, but felt like sharing my personal solution nonetheless.
Note: The 'NumpadAdd::!Esc' is how I switch, with a simple button push, between Sculptris and my reference image. The !=alt in AutoHotKeys code. Normally I use Alt+Tab to switch windows, but Sculptris makes the interface buttons appear and disappear every time you do this which I find annoying, so I prefer to close all other windows except my image and Sculptris and use this hotkey.
Also, I found that I prefer to keep the pen buttons disabled because they just make life more difficult for me.