I would buy three different grits Alex. Roughing P36 an P80 and P120. You might find that using an angle grinder sanding disc is more economical and flexible than a bench sander but you quickly find out what you use the most.
Just a tip which I'm sure you'll know already, but mark inside each belt if it's to be used with stainless steel. If you want to grind mild steel at some point use a different belt and mark that up. The reason for this is so you don't get cross contamination on your nice stainless job. I've seen rust SS and it's not nice.
Looks Slow but is Fast
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