Hey Guy,
I haven't tried to control the CG5 on OS X, but if I were to, the first place I would look is INDI. Cartes du ciel has an option to connect to an INDI server and the INDI server provided by Cloudmakers for OS X has drivers for many popular mounts. You can find it here:
http://www.cloudmakers.eu/indiserver/
I've actually been trying to get this working myself, but with an EQ8. Not having much luck there, but you might have more luck with the CG5 :-)
Cheers,
Lee