Hi Chris,
thats no good news about Sturmey Archer 
I can use my calliper gauge - at least I’m not sure about the precision of my efforts… I guess I’ll just try and see what I can buy. If I have the new bearing balls on my table, I’ll roll them together with the old ones between two sheets of glas to see if they differ in size. Should be precise enought. I think…
Stephan