Since your original question was what to do AFTER heat treating with nitrate and stains, and hardly anyone answered your question, let me suggest you use Jim Chambers oil finish. First coat goes on fairly heavily, so it can soak into the wood, a nice thing about Chambers finish is that it does not tend to run. Let it dry for 24 hours or so, then apply the next coat as thinly as possible with a lint free rag, again letting it sit at least overnight. I find that 2-3 thin coats, rubbed in with a lint free cloth gives a nice matte finish. If you want more gloss, just rub in a few more thin coats. When cured, I use Briewax to protect it. some people like to mess around with other finishes and that is fine, it is part of the fun of this. But, since I make money doing this, I don't have time to monkey around with finishes that take weeks or months to set up and may or may not provide any protection to the wood.