I would use a coating, no worry about that turning brown if can get the prep to come out right. I don't think there is much difference between coatings, Tuf Shine, McKee's, Optimum, Armour Detail Supply, they should all give you pretty similar results. If you are looking for something local you may be able to find some Turtle Wax Mr. Cartoon tire coating. Those are all acrylic coatings, which are going to be a white liquid, will give a blue hue for a few minutes as the acrylic is cross-linking, and will be glossy, do an additional coat or two for more gloss.