Moe...
I used Fieblings leather dye....dark brown. The horn is going to be aged so as I'm scribing it the finish is being forced on the patina. I want it look about 40 years old when done.
Fieblings leather dye works as well as any, the problem with those types of dye is that they don't penetrate the horn, not much does other than a long soak in a brine solution, but the up side is you can refresh the color every now and then, I've found with my horns that the longer they spend in the sunlight they take a yellowish almost aged ivory look, when I make them now I choose raw horns and try to be conscious of their natural color, get a small bottle of British Tan, that's my favorite aging dye, it gives a warmer finish than the dark brown.
When I engrave my horns I first choose a period appropriate event in my area of the country, being from southern New England I seldom run out of events to map out on my horns, I'm within 30 minutes driving distance from Lexington, Concord, Bunker (Breeds) hill, The cannons taken from Fort Ty were dragged a few hundred yards from my house on their way to Boston.
Also, I stay away from the shiny Mexican horns being sold commercially on the market, they are brittle, hard to work, and they crack easily.
Yours looks great, keep up the good work.