Well, my GO set arrived today.
The intersections on the board are 15.8mm apart, and the biconvex stones are about 12.7mm wide by 3.175mm thick.
I have 181 black, and 183 white stones.
Does anyone know of a source of go stones that could work as replacements if needed?
The original manufacturer of this set, The Game Keeper, i do not think still makes GO sets, and i have never seen GO stones this tiny before.

I found a set of similar sized pieces at aliexpress, but they are plastic, the originals that came with my set are real stone and shell. These are actually 1mm bigger in diameter, and a bit thicker.
If anyone else has a smaller then normal go set like mine and finds that they need a replacement or two, this is probably as good as you will find.