30% is too much nitro. All of the manuals I have seen thus far (Thunder Tiger, OS, Magnum, Super Tigre) recommend no more than 20% nitromethane, and most of them say that if you are going to use more you need to make adjustments to the engine (timing?). Mixing what you have with some 0% will give you a great deal on 2 gallons of 15%, which is probably perfect for what you need.