Hi

I have an Alpha 60 RTF I found that the evolution that comes with the Alpha 60 will fly it very nicely with a 12 X 6 prop.
I think the 11 X 6 will lack in low end grunt.

If you havent already pulled the stop out of the high speed needle valve you may want to do so, they make adjusting the needle valve a pita.
if you want to make it a little more responsive, play with your servo linkage to get a bit more throw.
enjoy!