Thanks everyone for the critiques and the complements. It's great to hear what I'm going right and wrong. I've definitely been working with my instructor on not coming as far out of the saddle on smaller jumps and she says that will come with time and practice - just a matter of correcting an old, bad habit left over from the Hunter ring. She's been having me trot larger jumps (not larger than I normally jump, just larger than we normally trot!) so I can really get a feel for being thrown out of the saddle when the horse pats the ground instead of propelling myself up on my own power, and I think that is really helpful, both for my seat and for forcing me to have a tight leg to support the horse off the ground. :)
It feels really weird to me to have the stirrup on the outside of my foot. I was trained as a kid with the peacock stirrups, so we were always taught to have the inside bar touching the ball of the big toe and then straight across, but I've read about doing it the way Amber suggested and am curious. Maybe I'll play around with it one day.
I'll make sure to get update pics, maybe at the clinic I am attending in December. :)