When you are setting up and cutting your header for your pipe, keep the pipe pushed up close to the header at the silicone connector. Then as you see you are getting too short for peak, just pull the pipe out a little in the silicone connector.

Single stage tuned pipes are used mainly for boats and all out speed planes. They have a sharp peak to their performance. The engine does not run better than with a regular muffler unless operated in this narrow peak range. Also these engines show the most improvement in power when operated at a higher rpm with a small prop.

On the other hand, the quiet pipes are sort of a two chamber design that exhibit a broader power band that work great for pattern airplanes.