I've just bought a pair of 'aero' style roof bars for my car, and intend to use a roof mounted bike carrier (x2) from now on. Trouble is I have no idea what to look for and what to avoid.
Other than knowing 'Thule' is a highly regarded brand, what models/types should I be looking for?
What's the best fixing system?
I have been using a Saris Bones rack on the rear of my (former) car until now and despite being happy with it im not convinced its the safest method of keeping the paintwork intact on my seat tube, nor is it a great idea to repeatedly expose the paintwork on my boot/bumper to associated wear and tear.
Are the through axle types better for fixing bikes to roof bars, or down tube grips?
Whats the most comprehensive and best regarded out there?
Example links would be appreciated.

