Os #8 plug on my 46AX as well and an APC 11X6 although I intend to try a Graupner in the near future.
I run mine on 10% with great performance.
I have never tried a carbon fiber prop but can tell you from using carbon fiber blades on my helis that they are more brittle and I would imagine even a minor ground strike will shatter the prop where a plastic prop would have survived intact.