I have the TT61 Pro on a Global Right Flyer 60 with an APC 13x4W. I started with an APC 11x7 and it was just too fast for a beginner and even my instructor commented we should slow it down some. We get a really good slow idle, but several times, he had to kill the engine to get it to land.

My muffler still has the baffle and I'm using Magnum 10% fuel.

If I remember correctly, these are my tach readings:
11x7 = about 12800 peak rpm
13x4W = 13100 peak rpm

I really like the 13x4W. It does require a higher throttle setting for cruising, but the instant acceleration makes up for the increased fuel consumption; and it really slows down for landing.

Now I just have to learn to land the thing by myself.