I noticed, and felt like sharing, after I watched and followed along with the Qigong session 6 video that when you make your breath hair-thin or wide open that they can switch places.
If you zoom down, down, down into smaller and smaller places with the breath (making the breath smaller and ever smaller) it reemerges at a large opening or the wide open breath. Same with the wide open breath; making it larger and larger and bigger and bigger, one can kinda space out and not notice it just reemerged as a teeny-tiny breath.
With both of these, I feel I notice when they reemerge they show how you can take it further. I.e. is the breath going from great big to itsy-bitsy as small as it can go? When you go from iddy-biddy to brobdingnagian, is it as gigantic as it can get?
You can keep chasing down how to open things up more by jumping scale with it as it goes and further trying to make it larger or smaller. Because, just because you’ve made the breath so small it becomes large again doesn’t mean it is as large as it can be, neither the opposite.