Holding option and trying to move the guides around in loupe overlay will not work, also the the grid size and opacity won't respond to input (holding down command). The problem exists with graphics acceleration on and disabled. Using OSX 10.9.5 with a Wacom intuos tablet.
Hmmm, that would be great if I had an alternative. I'm pretty sure I'm not the only one in the photography world that only uses a Wacom. Probably should have been a fairly high priority to get the software to work properly with them before release.