I use Zaino Z7 wash mixed in a spray bottle. While the car is still wet after washing it, I just spray on the Z7 lube and go for it. It works well, rinses completely clean, and is dirt cheap. When I finish a panel, I rinse the completed panel, wet down the next pane, spritz Z7, and go for it.
I don't think that Z7 has magical properties. Any decent wash should give the same results.
Dan.