I have used 5/16-24 UNF Kaynar nuts MS21042-5 from LAS Aero. https://www.lasaero.com/products/article/CUB8AQL The gaskets look like the correct type but I have usually got them from a Morgan dealer at a surprisingly good price.
nice color on those jetnuts. i just used black anodized ones but the gold would have looked better with the titanium wrap.
2019 M3W Sold and is now in Las Vegas enjoying the showgirls :-)