My quark seems to be one of the "tail drifters". It will tend to rotate CW during a flight and I have to compensate with trim.
Since I had experience with this on my Blade 400, what I do is this:
Turn on the receiver.
Put the tail trim slider all the way to the left.
Turn on the Heli.
This way I have lots of right adjustment. I tried restarting the Heli part way through the flight but it didn't help.
Would be nice if I could fix the Quark the same way I fixed my Blade... With a GY401!