RE: servo/boost tabs
Servo tabs can function per full scale but the results are NOT the same .
Simply put - the model is too small for the forces produced to be of much use
Also servo tabs only work around the neutral position- Again simply put - you can't get something for nothing.
Think about it - If you are going to produce a down force (or side force) you have to to put at least that much force into the task
Aerodynamically counterbalanced control surfaces will produce high forces with small energy inputs.
You can use linked tabs (tab linked to the stationary surface such that the tab moves a LOT in opposite direction of the control surface). This works but if all you want to do is decrease cost of servo - ferget it
You can buy really good 300inch ounce servos for 10-20 bucks -really -that are extremely good. The only other necessity is a really good power supply to the servo -
I would not use anything on a large model but A123 batteries and good 22ga wiring.