I'll try and do one sometime this week for you of some off the pattern exercises and slow work with her...It would be nice if I could find one of the more finished barrel horses to show you but it's kinda hard to catch them these days.
In regards to QH's video yep, that's pretty much it, I'd back up and then swinggg that hip in though a lot more than what she did with Squiggy. It looks like Squiggy has it a little more naturally than Sunny does however.
I normally bug her to push her hip over more and more around the whole barrel as well, but it was bitterly cold that day and I just wanted to be cuddled up on the couch with a big blankie, not on my horse. It was one of them days....
As you said, she has it a bit more naturally than Sunny. She's always got more of a bend and works off of her hiney more than her front.