My 2 cents is probably worth 3 cents, but I will share my finds. I have used all blacks available, and vinegaroon. I have settled on Angelus Jet Black, after applying and drying, I go over with a coat of Fiebing's Show Brown. After drying I buff, and the brown seems to lock in the black more. I find less buffing is required. Apply the sealer of your choosing. Once sealed it is very hard to tell the brown is even there. Try it out on scrap, and see what you think.