You’re welcome. Good luck.

The “more tension is less” that you mention isn’t quite what I wrote.

What I wrote/meant is that the tension is in the aperture corners, not the middle of the lips–which is the area that interacts with the air and must be left free to vibrate as fast as possible.

And the tension os only as much as necessary. It’s best to lead with the air and let the aperture corners respond to the air; this can be a split second but makes a big difference between actively blowing air through the instrument versus releasing air like Greg’s bow and arrow analogy.

I can relate to your observation that sometimes you get a pitch with less tension and sometimes it takes more.

I have encountered this before and have used those experiences as clues into playing more efficiently.

It’s probably because you reduced the size of the aperture and don’t have unnecessary tension, therefore you aren’t fighting against the instrument / yourself.

I play most days parts of music I was experimenting with previously when I had that experience to see if I can replicate it again and understand it better. For a while, I wasn’t sure if I’d be able to do it again but in time I stopped doubting it and it became my new normal. I still play them occasionally, but it’s becoming less and less now as I no longer feel the need to and there are new things that seem more relevant to my playing, goals, etc.