Rog,
In your 1/4 scale example, you have 1/16 the area in the wing too. As far as CG range, in a model we don't typically have to worry about carrying two fat cousins in the rear seat with empty fuel tanks at one end of the loading spectrum or flying solo with full tanks, so the CG problem is minimized. Some of us even have the tank at the CG to avoid trim changes with burn, which allows very small tail surfaces (around 10-12%) in very special applications.