Two quick comments:
1.) If you are going to use 303 Protectant be sure you get the product for fabric tops not vinyl and be careful applying it. I believe there are photos or a video to cover the rear glass and any other surface that could get the 303 on it.
2.) When I ordered my top from BAS I asked about using a protectant like 303 on it, the reply I got was that they were not familiar with 303 but they sold a protectant that I opted not to get as they also said the top fabric was already treated and should not need re-treating for a year or more based on exposure to the elements.