Don't go via Tobermorey!!!
I went out to Jervois after the grader in a 4WD and its still a hard slog. Without long range tanks its almost impossible and the recent rains have turned it all to soup.
Divine Winds route is the only sensible way but I'd do shorter legs and stop more. Unless you have air cond, this is NOT the time of year to try it, you will dehydrate quicker than a schooner glass in Rorkes.
Besides, unless your gonna make a habit of doing the "track", act all touristy and look at it all.
All the advise above is good. Stop every hour/100K or so at a watering hole or suitable place, don't stop on the roadside unless you REALLY have to, road trains rule and they wouldn't even feel the bump.
It's getting DAMN wet up here every so often so DON'T try to drive in the serious stuff if you haven't had practice and don't have to do it, you can loose the road in the mist.
Anyway, enjoy. The first time is always the best one.