N.S.
Found these online for you, but no one offered quantities - maybe start with a little bit, then figure out how much for the larger amount:
"The easiest 'rule' to remember is that to mix a brown you mix a primary with its complementary color, so purple and yellow; blue and orange; or red and green."
Another place said red and green also, so you might want to start with that.
Yet another place said to said start with red and yellow to get orange, then add blue, so that might also be a winner; but since you probably have bottles of red and green, that first way might be your easiest first attempt.
Good for you, by the way, for making it yourself! :-) Good luck!!!