For me I feel like I found a better option. The other vintage aircraft ones ones I’ve seen people using and I bought some have the interior chamfer to almost a point which is inaccurate. Plus for these more correct 10 pin Marconi the hole isn’t big enough for them to fit through. I was having to flip them on the other side so the top of the washer was wider, boring them out for a bigger I.D. putting a new chamfer on that side and sanding off the brass color. The only benefit was they were vintage. These ones I found just need a chamfer which is the hardest part, but they are closer in the other ways described. Maybe next time I’ll find the exact ones. Fingers crossed.
Don't forget to post some pictures with the Marconis when you have it ready