My experience is:

1) By the time the wind get's high enough for me to consider using the downhaul to depower, I am too busy to remember to release my downhaul.

2) When I am going nearly dead downwind, to avoid pitchpoling, it's time to go in.

To brobru - My A-Class, a Marstrom, is much more forgiving downwind than a 5.5uni or 17. I was sailing in conditions 2 weekends ago, that would have been a certain pitchpole on a 5.5uni. It only only meant "stay alert" on the A.

Carl