Steven,
What is the base of your stain? Is it an oil? Is it acrylic? What is it?
If it is acrylic it will laught at that mix at that concentration without an added booster.
If it is oil it would need to be a fairly weak oil ( less drying oils in the formula) to be removed with that concentration, and it's age and exposure factor into it too.
Post a pic and tell us more about the coating.
Beth
p.s. yes, I would boost the hydroxide first.....