We recommend that you only clean the hard top in the following way:
Use a sponge to remove dust and loose dirt on the hard top surface.
Wipe the surface with a soft, damp cloth and a mild soap and water solution.Dry the area with a clean, soft cloth.
Make sure the surface of your hard top is dry before applying a small amount of conditioner or spray wax.
For additional information and assistance, we recommend that you contact an authorized dealer.
Note: Test any conditioner or spray wax on an inconspicuous area before applying broadly.
Note: Do not use alcohol containing cleaner or any type of solvent on the hard top surface.
Note: Do not use power tools, paste wax or polish on the hard top surface.
Note: Do not use chemical solvents or strong detergents when cleaning the hard top. If any chemical solvent gets on the hard top surface, remove it immediately from the surface to avoid unrepairable damage.
BUT, this weekend I took the plunge and used a (weaker) ceramic coating. Unfortunately 303 only lasts 3-5 weeks—fine for the summer, but in the winter months with snow and whatnot it'll be a hassle. (If I had a garage I'd probably just use 303 forever, but I don't.)
So far so good, but... it's been only 24 hours at this point.