Successful open crumb with 65% hydration

I have been trying to achieve an open crumb with 75% hydration but today I managed to achieve a nice open crumb with 65% hydration. This was the result of long autolyse and fermentation, gentle handling and lower than normal temperature baking. I am happy with the results and got me to appreciate that what goes on to achieve an open crumb is many other factors than just increasing the hydration level.
Have you managed to get an open crumb too ? any other technique you can share ?