On our test stand, we run the SuperTigre G2300 with an APC 18 x 10 prop and Omega 10% fuel. We expect to see RPM levels in the low-to-mid-7,000's. That's with the stock muffler. The engine can be safely run up to 10,000 RPM, depending upon the propeller, though most don't go over 9,000.

Your numbers sound about right. Remember, the engine will "come in" over the first few gallons' worth of running, so don't be in a hurry to get it leaned to peak RPM. Work with it gradually and it will be a real "keeper".