I don't use powder of any kind.
I applied Turtle Wax upon receipt (yes, regular auto wax), per the recommendation of the maker (Hilinski), and it has been effective for quite a while.
Actually, they simply say to use 100% Carnuba wax. To the best of my knowledge, Turtle Wax is not, so be careful. Most car waxes have a small amount of abrasive in them, so using just a generic car wax on a semi-regular basis is not a great idea.