I prefer to customise it for you and sell you a print or printable file 
Cool project and I think I saw similar thing recently when I wrote about metal seed backups.I see you written nice Bitcoin Talk, so do you have your own stamping tools and letters or you borrowed it?
What about rust? I know that's usually not a problem with washers I've had laying around forever, but if it holds crucial information, I wouldn't mind oiling them before bolting them together. Especially since this won't be in a normal drawer but probably somewhere well hidden.
They are stainless steel washers, rostfrei, meaning free from rust, but it is possible to develop some rust during long periods of time, under special conditions or if weaker alloy is used.I think that painting would be a better protection solution than oiling them.