How is my horses conformation?

He looks like the typical Appendix QH. He is built down hill slightly but that's just the QH trait, they are bred that way. With more work into him the muscle will come up very easily and he will look awesome. Id just work on a lot of up hill work to make his rump look a bit more round, so the slope isnt so defined as it is at the moment. But that again is a QH trait. He is just a typical bay, a lot of horses get darker in winter because their coat grows thicker. Looks like you've got yourself a best friend :)