Very nice trees. The degree of branching is great. Well done.
I myself am not fond of trees that are perched high with the surface roots more than half exposed. I would not change the depth you have your trees potted at. My tastes says the top of the roots should be just barely visible at the soil line. But of course this is my personal taste, and looking through the latest Kofuku ten images, this seems to be the common way to plant pines. Except of course for the deliberate exposed root styles, and then there are several inches of roots exposed.