I cleaned a total of 15 cars today, using just two 3 gallon and one 1 gallon ONR W&S solutions and the BRS. Cleaned cars sitting on a dealer lot, all pretty dusty/dirty, from several months of no cleaning, and it was a hot day.
After cleaning about 5 dirty cars with it, the black-hole look-a-like ONR solution didn't perform very well on a baking hot black car in the sun haha. Who would have thought!
My fastest car, a Ford Ka from 2004, took me Approx 8 min.! I didn't clean the wheels and on some cars I did 'spot-repair' (cleaning stubborn parts of dirt).
I basically clean the whole car with the BRS, (Yes the car dries almost completely due to the sun and the heat, leaving polymer spots.) then take a damp cloth and a dry MF towel. For windows and hot dark-coloured cars in the sun, with a dirty solution,I use both towels. With brighter cars, the damp cloth was sufficient for drying without smears!