Gents,
Sounds like there's an agreement here. The issue is that most RC model pilots are not full scale pilots, so some concepts written by full scale pilots need to be sometimes over-simplified to be easier to understand for those that haven't "felt" wind or compared ground speed to indictated air speed.

The "best" way to tell "indicated" airspeed with an RC model (IMHO) is by angle of attack in level flight for a given configuration (flaps up, gear up, or flaps down gear down).

A great way to teach this concept is to have an RC pilot learn how to fly a perfectly round circle, level, at a constant perceived speed in moderate winds. By starting into the wind at about 3/4 throttle, flaps up and gear up, the circle can be flown level and round by adjusting the throttle and bank angle. Downwind throttle might be as low as 1/2 throttle to keep the speed constant, but it should still be well above the stall...notice the the angle of attack (AOA) will be higher, more up elevator (trim) in for level flight.

Flying this circle several times should cement this into a willing student's mind, at a safe altitude and well above the stall. This lesson should translate well to the traffic pattern where it is much more critical.

Goal: When flying the same level circle leaving the throttle fixed at 1/2 (or 3/4) with the same model and configuration a person can see the difference in perceived speed (speed relative to the ground), with "indicated" airspeed (and angle of attack) remaining constant.