Sounds like a lot of fun! I've been toying around with that idea myself for quite awhile. My big mare knows a fair bit but that's one thing I've never done. You're recap makes me really want to look into a bit harder.
I totally agree with paying for the pain. If you don't hurt, you didn't do it right.
Riding western all my life and even riding with trainers, body position was not something that was ever harped on. I got a different perspective from the lesson and getting the same or better result.
Plus riding by myself all the time! I ended up turning down a riding job a few months ago and so I am still riding alone. So even having someone watching and giving input is a help if that is the very least I got out of it :)