Doh, I was still typing while you posted.

Yep, supposing we do that now with sub-trim.

The drift is seemingly not a constant and occurs so slow (like trying to watch grass grow) that I wonder - I will do that though and possibly substitute some other analog servo I have lying around to see what happens if that's compatible with SAFE/AS3X.
Just for the record, the servo didn't budge from position when hooked up to the driver and left for 15~20 minutes but perhaps because there was nothing to excite it like when active under AS3X...

BTW, not that it necessarily means its still okay but I just exercised the rudder servo manually, full throw, by hand and felt no inconsistency or roughness in the gear train.

Thanks very much for your time on this issue; your help, experience, and expertise are greatly appreciated.