I think 14,000 rpm is a bit high for stunt. 10,000 rpm is closer to what I look for before launch, sometimes even less, 9500 for my Fox 35 mounted on a Bi Slob. I normally launch at a very rich 2 cycle or even richer 4 cycle.
The stunt pattern requires climb capability similar to RC 3D flying, therefore, brute horsepower is NOT what I look for in a control line engine. Torque is what you need to turn long, low pitched, climb propellers. Consistency is second which often means awesome fuel draw from smallish venturis. Much different power profile than RC.