Quick question(s)

I'm working on finishing up a Tamiya 1/48 scale P-51D.
The decals in the kit come with white circles as a background for the largest U.S. stars. The model was done using foil. Do I need to use those white circles? Another question, what about Micro-Sol and Micro-Set. Has anybody ever used those on top of foil? I have added a coat of Future over the entire model already.
Thanks,
Rich