Too late!
I got my pylon APC 8.5 X7 yesterday and I tried it. I don't want anything else now. Very impressive acceleration, I have less pitch than the previous one (8X8) but I go faster in straight line, and when I turned, wow it doesn't loss speed...
I tried also a modified APC 8X9 to 7.5 X 9. Very fast out of big dive, but loose too much speed on level flight, and it too slushy in curve.
My Shrike is a bit heavy with its 2.8 pounds, and the wing are not so thin. I need thrust!

But its good to know it, the winter comes fast; I want to build something really fast this winter, who can run a 7X9-10-11 at 20 000 rpm and more.
I want to break my 145mph barrier and go like 170 mph...