When flying on my own, I would agree that it would be more fun to use the free channel for MOD.
But when training you will fly 2D anyway and the GAIN channel pot lets you "challenge" the student progressively. Therefore I wanted to assign the free channel to GAIN but then I lose the neat switch-flicking trim reset function.
Someone want to try an experiment , I would but I am to tied up in other projects at the moment.
Normaly Rudder is or can be set to full servo range as in full CW ,full CCW and ofcourse cetered. These are the same outputs required to reset Trims on Guardian 2D/3D so...........
Seems one could disconnect Rudder signal from Guardian to receiver and plug Guardian Mod. lead into Receiver make Trim Reset and then switch leads back. Yes it is a pain bvut should work I believe.
It seems one could also use a spare receiver and receiver battery and connect this receiver to the Guardian 2D/3D Mode channel and along the same lines a servo tester should work also.
Perhaps Bill or John will comment on these ideas.