Good job, Neal! It sounds like you're doing them pretty well.
Not to complicate your life, but here are a couple of things you might find helpful. Try them, anyway. Instead of focusing on pushing through your heels, try thinking about pushing the hips forward. If you can feel your glutes contracting that will help with this. Second, the bar doesn't have to hit your shins hard, just lightly glide up them. I have had a tendency to pull back on the bar, pulling it into my shins. Now I'm keeping my body a little more forward over the bar, and the bar comes straight up. As I extend, my shins move out of the way, and the contact between them and the bar is very light.
I agree with Ken about adding weight. You'll be surprised how far you can go. I'd go ahead and move up a bit. In fact, you can play with weight a little. Just do little sets of 2 or 3 and experiment with raising the weight. Don't try to push it into difficult weights, but just get a feel for higher loads. Do that for a few weeks before settling on a working load.
Our greatest fear should not be of failure, but of succeeding at things in life that don't really matter.--Francis Chan