Da Rock,
I agree that as RC pilots ground effect is hard to perceive but is still there all the same. Try taking off at half throttle or something less. When you reach the point that you can fly within a wingspan of the ground but cannot fly higher without adding power you are in ground effect. What you describe “that sometimes the plane seems to not settle.” is due to ground effect. Re:
“If, during the landing phase of flight, the aircraft is brought into ground effect with a constant AOA, the aircraft experiences an increase in CL and a reduction in the thrust required, and a “floating” effect may occur. Because of the reduced drag and power-off deceleration in ground effect, any excess speed at the point of flare may incur a considerable “float” distance. As the aircraft nears the point of touchdown, ground effect is most realized at altitudes less than the wingspan.” Reference Pilot’s Handbook of Aeronautical Knowledge Handbook Chapter 4 Page 4-11.
[link]http://www.faa.gov/library/manuals/aviation/pilot_handbook/[/link]

Regards
Frank

"Takeoffs are optional. Landings are mandatory."