As a valeting novice, the one thing I can tell you is that until you get it spotless clean it's not going to matter too much what you use. Once clean, polished and waxed then it becomes a matter of maintenance and the last thing you want to do when it gets to that stage is use something that removes all your hard work of laying down layers of protective sealants and waxes.
The first job then is to get it clean
The second is to get it polished
The third is to get it protected
then to get the shine enhanced
then you maintain it when what you use to wash it becomes important.
