Hello bhp,
Dick Blick waterproof india ink can be found in an art supplies store. Or over the internet.
The reason I selected the Rhomlas is because of the finish. Oiled. Stippled, which I find nicer, is lacquered. Oil finish can be taken out with denatured alcohol. To strip lacquer I will quote from a gunsmithing page,
" Removing lacquer or varnish finishes is easiest with general citrus-based paint strippers, which you can purchase at any hardware store. Brush it on, let it do its work, then blot it off. Don't rub, scrub or try to help, you'll just press the old finish down into the pores of the wood."
After you let it dry overnight, then use DB. Probably will need two or perhaps three thin applications. But it will look like ebony. HTH.
Pics probably will be taken in November. Schedule of friend with camera. And I still haven't received the Nill's. Will try scanning it, though. See if it works.