Be sure to let us know if you need a bolt length upgrade as well so we can quote you the correct bolt lengths. Typically, if you are going into treated lumber, you will need the longer bolt length unless you are counter-sinking your t-nuts.
Also, keep in mind that if you need stainless steel bolts, you also need stainless steel t-nuts. Nicros also carries these – please call for a quote. Note: Keep in mind, if you are using stainless steel hardware, you will also want to construct your wall using stainless steel fasteners.