Just a thought
Since my last post on this thread I have been playing around at countersteering - plenty of opportunity; I'm currently working as a moto courier - and found I was doing the following:
I regularly use a long left-hand slip road, completing 270deg or so, that leads on to a dual carriageway. It's a safe(er) chance to practice left-hand bends, which in the UK are potentially risky compared to right-handers since the tendency, if drifting wide, is to run into oncoming traffic. Also, we get plenty of practice at right-handers on roundabouts.
This slip road's curve tightens slightly as it reaches the dual carriageway. Anyway, I found that, at maximum lean, I was trying to 'steer' the bike around the last, tighter part of the curve by turning the bars to the left, despite being aware of countersteering and using it consciously to initiate turns. The result was a drift towards the gravelly stuff on the outside.
Seems to me that, while it is easy enough to get the hand of countersteering to start a turn - since it is what we do anyway, consciously or not - it may take a lot more mental effort right on the limit. This was my experience on this bend, for sure. I didn't find myself doing the same on similar right-handers, maybe because, until recently, I was getting less practice at bigger lean angles while turning left.