Well, I haven't used those pads, but as per the descriptions on their site, I'd go with the following:
SFX1A fast-action, swirl-free machine polishing pad for trouble-free repair of damaged, weathered and neglected paint. Use with Sonus Restore (SFX-1) or other compounds and paint cleaners designed to remove 1200 grit sanding marks.
-Sounds like this is for severe damage. You don't have any compounds listed. Always try the least aggressive method first. You may not need to use this pad, depending on your paint condition. You could try using the SSR1, but I don't think it would be recommended.
SFX2 A gloss-enhancing, swirl-reducing polishing pad for the regular care of paint with minor imperfections.
Use with Sonus Enhance (SFX-2) or other “swirl-remover” machine polish formulas.
-This would be what you'd use with the SSR1 or PwC Blue.
SFX3Use with Sonüs Final Finish (SFX-3), Sonüs Paintwork Cleanser, machine glazes, sealants and liquid waxes.
-This would be for the EX-P and Natty's and even the PwC Blue, once the marring has been addressed. (I find it just as easy to use Natty by hand, though. Also, you can get into the corners, around windows etc. better by hand than by machine. All you are doing is wiping the wax on. There is no hard rubbing, such as with a polish, so except for getting a thinner or more even coat, you may skip applying Natty's by machine.
Hope this helps. :smt102
