So as a final couple notes to this, even using the SP4 driver still does NOT allow you to change the side button, only the "Eraser" button.
And as a warning, in its current version, I would NOT install the SP4 driver because it is the same version as the SP3 one that was crashing everyone's SP3 on the 1/19 firmware update. I did and was getting all kinds of flakey things happen and lockups and blue screens.
I have not been able to find a prior version of the SP4 pen drivers that works(I'm not sure one exists at this point). So, for the time being, be warned if you do do this method.