Where we start depends on the damage needing repair. Any dings or deep scratches will get bumped outward from the back side JUST ENOUGH to hide the defect, no more. IE: better to have to bump twice than sand through. For something with such defects, we start with 360 grit w/d. We use that grit because I have it. If you have 400, so be it. Use this until defects are gone. Next, 600. Or where we start if there's no defect other than 60 years of scratches. Next, 1200, then 1500, then 2000, then 2500. All w/d, and just like doing clearcoat, if at any point the paper you're using leave behind some scratches, back up one more grit because the last one didn't get them out. Keep in mind, stainless is a much slower sanding process than clearcoat. But we've found this is a much better method than using the sisal wheel, as it leaves fine grooves in taking out other defects. If you have a scrap piece, that's the one to practice on..