Agree - Start with the mildest first and use harsher if it doesn't work. Rubbing compound is very course and will leave small scratches. If you use rubbing compound, you will need to use polishing compound then a polish then wax/sealant when you are done. It is like sanding wood. 80 grit then 100 then 150 then 220 then 320 etc.
I found the new polymer sealants last much longer then the old carnauba waxes,