By all means stick with what works. I do have "good ones" by the way, and they run perfectly, always have(even the first 15 tanks). Two strokes will give you maximum HP at high RPMs, it's their nature. Get a tach out, try different props, fly with them and find out what works the best on your plane/ engine combo and go with it. Mine and others I know of really come alive when they are allowed to rev up.