Your horse is absolutely stunning. I love, love, love, love dapple grey's! The color has always been my absolute favorite!
I have nothing to say about her conformation, that's not my gig - but I can help with you a few things with your form.
Your jumping pictures, in the majority of them you are appearing to be jumping ahead.
This one here:
See how your crotch is over the Pommel of your saddle? See how much space is between your seat and your saddle? You anticipated the fence, common error many, many make.
Your leg is nicely at the girth, which is great - but you are not allowing your heels to do their job. Which is anchor you.
In this picture here as well:
Same thing. You aren't as ahead in this one as you were in the first. But here you have lost your lower leg, and again - your heels.
We want our legs glued to that girth. Your toes shoud be just at the girth. Pretty much what Anebel stated, I agree with. But I do think the issue isn't the length of your leathers *they are at the right length - we want 110 degree angle in our knees* the issue is that you have no muscle memory to keep your legs at the girth.
We want to be wrapped around our horses, not just ontop. Our legs must be wrapped *in sense* around our horses girth. This not only aids our seat to be dead on, but it keeps us locked and secure in our tack.
I invite you to look at Beezie Madden's pictures, and pictures of riders back inthe 50's. Beezie Madden definately, is one rider to really look up to for very fucntional form over fences. Look at her legs, majority of the time they are locked at that girth.
We do not want our toes to fall back off the girth, nor do we want them to surpass the girth.
You also really need to open your knees and allow the weight from your upper body, to sink down into your heels. Our heels MUST beable to do their job - that job is anchoring us into our tack.
The two work hand in hand. Leg at girth, heels absorbing bodies weight.
This picture here:
You look pretty good, but again, you've lost your lower leg. And your heels are not doing their job.
Your seat is pretty good. Not ahead, not behind. It is pretty close to being smack dab over the center of your tack. I love your back, and I love that you are looking up.
Here is a shot of Beezie Madden. See where he leg is - that is exactly where we want to be :)