I do not know where the 10k came from. Mine spins a 13x6 K series at around 9.000 too. In a French journal they guys got 9.000 as well. I switched to a 12x8 K series (peak at 9.400, practical rpm 9.200). This prop gives me more dynamic flight performance.

I think a current O.S. (Alpha series) is far better than a current Thunder Tiger. But for a change, buying a TT can be fun.