If we think about what pitch trim is for (provide a means of trimming the aircraft for a specific speed, flap configuration, and C.G. position), it should quickly become obvious that comparing settings from one RV model to another is pointless. Even comparing two of the same model may not be useful depending on the C.G. that is typical for landing.
I have walked the flight line at fly-ins and have seen trim tab positions (likely still where they were at landing), in positions from one extreme to the other (nose up and nose down).
Sometimes even a lot of nose down (a strong indicator that the airplane was at or maybe even beyond the aft C.G. limit).
For most RV's the ideal trim tab travel is such that allows about 30-35% of the travel to be nose down trim, and the remainder to be nose up trim.
This will allow for being able to trim for a normal approach speed at full flaps at C.G.'s typical for landing (though it still may not be enough when near the fwd end of the C.G. range).
The ideal trim setting for take-off will vary with C.G., but because the control forces on RV's are lighter than many production aircraft, as long as you are close, take-offs are generally not a problem and you can make a small adjustment once stabilized in a climb.
Having said that, my opinion is that every RV should have means of easily determining the pitch trim setting for take-off. Doesn't have to be fancy. For my manual trim RV-6A it is knowing that it is at neutral when the knob is about 1" aft of the fwd limit (no other indicator required).
A take-off with a grossly maladjusted pitch trim (because of having landed with a majorly aft C.G.) can cause quite a surprise, and in some conditions require some major effort on by the pilot to counter act.