I always enjoy your posts about Klassy, your enthusiasum is hard to ignore!
I am glad that she came back to you, but it sure would be nice to know what was going on there. All I can figure is that it was a "heat" that lasted a long time.
As far as you position, the two main things I see in almost every picture are that your rein has a downward pull to it. I bet that in your hand there is much more pressure on the part of your hand where the rein exits, next to your pinky. You are trying to get her down by using a very slight, but perceptible, downward angle. I know that sometimes one can use a lowered hand to encougare a stretchdownward such as in long and low, but if you do this, you would also give forward.
Klassy has a neck shape that bulges out a little at the bottom. The lower curve of her S curved neck is rounder than optimal. If she pulls against your hand this curve will actually become more pronounced when you wish to reduce it's prominance by building the upper neck muscles and lifting the lowest part of her neck as much as possible. This is where the long and low and the so-called "neck telescoping" gesture come in. I take this name from works witten by Dr. Deb Bennet. Her writings on anatomy of the horse and how it affects riding and performance are well worth reading.
I would encourage you to actually RAISE your hands to encourage Klasssy to lower her head. I would love to see some photos of how your ride her long and low and what she looks like when she is given a little more rein.
These are just some thoughts, things to experiment on.
The other thing, and you mentioned it yourself, is your leg being forward of the best lineup for carrying you correctly. It's king of like, hm m m , you are perhaps pinching with your knee, because I have this feeling that your weight is just not comign all the way THROUGH your knee and down to the foot/stirrup. This is also seen by the way your heel comes up a tad; it isn't receiving the firm weight it should be carrying.
All these points look better in the canter than the trot. It seems easier for you to be kind of "in" your hrose, than perched 'on' her as it feels in the trot.
I imagine you do stirrupless riding or lungeliine lessons, no? Those always help (it's been ages since I've done it, so I feel a bit hypocritical to say this stuff)
I might try pretending I was a cowboy from time to time and riding one handed, letting my legs really hand down and just feeling like I am draping down into my ankles/heels.
The other thing, and someone mentioned this before, if the saddle itself doesn't fit YOU, it can put you in a chair seat. If the pommel is too high, you will be always riding a saddle that feels like you are "climbing a hill". It ever so slightly forces the upper body to be forward, and also the lower to counterbalance the upper and you end up perpetually behind the motion, especially in the rising trot. Look at your saddle. The cantel should be about an inch higher than the pommel.
Ok, that's it for me. Hope you have many more amazing rides!