Very nice restore ...
I've done the same handle and love the shape. Opened mine up to 24 mm and dropped in a TGN Bristle Boar Knot. I'll be giving it a first try in a couple days. The lettering on yours is in much better shape than mine, which was mostly gone even before I polished it.
I probably would have tried either a white artists pen or white nail polish and then wiped off the excess. If that didn't work then I'd probably just quit and leave well enough alone.