Transmitter Based Tuning

Has anyone tried Transmitter Based Tuning?
http://ardupilot.org/plane/docs/common-transmitter-tuning.html

I’m having a hard time getting a good tune on my Quadplane, especially for QLOITER. I want to use Q_VFWD_GAIN to apply forward thrust rather than nose down to penetrate the wind, but it only works in QLOITER.

The problem I’m having is that I keep getting an error message, long before I see any noticeable oscillations. There is no mention of these errors on the wiki page, only this from the parameter description:

TUNE_ERR_THRESH: Controller error threshold
This sets the controller error threshold above which an alarm will sound and a message will be sent to the GCS to warn of controller instability

I don’t understand enough about what the error is trying to tell me and whether to heed it or increase the threshold. Is it meant to be a way to tell me that I’ve reached oscillation and its time to cut that value in half?

Please share your experiences tuning a Quadplane.