C5 Is the same product as C1 and is used as a hard coating to protect better against marring, holograms, and damage from brake dust etc. It's also designed to last for a longer time 12-18 months. As such, it doesn't function like a wax or the highly repellent nano coatings. You have to add these on top to get the hydrophobic affect that you are talking about where it washes offer ally easily.
So the ideal protection is C5 plus a coating like Exo/C2 or as in your case a wax. Long lasting protection for the wheels and easier to clean.
cheers, Steve