[Zee]

Servo tabs works on models well. Servo tab is like trim tab on aileron/elevator, just like Flypaper 2 is showing in the picture. I try those on model of Extra 230 elevators.

The spades do not work on models for one simple reason, you have no way to set it up properly.
The angle is critical and on full scale, way to set it up is go fly it and feel the stick pressure and if need shim it up. You do not feel the control pressure on your TX stick, so how you know that you actualy not adding load to your servo?
You could matematicaly figure out the angle of the spade, but until you test fly it and see what the controll pressures are doing you don't realy know.

I used the aileron and elevator servo tabs on my full scale design with good sucess.
Weight counter ballance, like on aileron is also good thing.

Zee