Eugoogoly.

Don't worry about only having a small amount of movement on the steerable wheel, you only need very small amounts.

With regard to your ailerons you may have some differential set in the radio that will make the servo move more one way than the other, or you may have produced the same effect mechanically. Difficult to explain but make sure that the servo arm you have connected to the aileron is at 90 degrees to the front/back alignment of the servo (ie it sticks out to the side) when the aileron is at neutral. If you want to set differential my understanding is that it should be the other way round, ie more up movement than down.

My personal view is that in the circumstances flaperons are an unnecessary complication, you won't need flaps on this sort of model and will have your hands plenty full with the main controls until you get used to it. There is a temptation to use the functions provided by modern computer radios simply because they are there, my moto is K.I.S.S. (Keep It Simple Simon), my aim is to use as few functions as possible, less to get wrong, less to check, less to remember to transfer to a new radio or model.

Hope the test flight goes well.

Simon.