I use Transtint even if it doesn't want to mix. Just put a little in the oil, mix it up really well and slather the oil on. No fuss, no muss. I tend not to overthink or worry about such things. With finishing, try something and if doesn't work, try something else. It's really hard to do any real damage to a stock.
You could also use something like Laurel Mountain Forge's dye stains and add them to the oil. They'll mix okay, I believe.
Jim