I want to order a small stock of metric hardware to keep on hand for my airhead. I'm thinking a good stock of wave washers, common nuts, and a few useful bolts. McMaster or Bel-Metric for the vendor unless you've got a better recommendation. There's a Fastenal and Grainger locally but I'm kind of offended by their pricing. What sizes and spec should I order in each? With all the EPA restrictions what is the most rust resistant finish for nuts and bolts these days? I'm not enamored with stainless steel except possibly for the wave washers.