RE: Mixing for KE help.
A completely neutral plane is almost impossible to get - even the latest greatest F3a models will need some mixing to fly right in all conditions.
If the plane is built straight and the cg is in about the right place, the rest must be done with mixes - this is normal and isn't "cheating" like some people think. If your plane tends to roll left slightly, you re-trim it to the right don't you? No-one would fly around having to hold in trim. Mixes are no different.
James