Yes, pretty much. You have an excellent shot with the "trainer." I'm just trying to say, at release, your shoulder blade on the back should TRY to move still more prominently back -- stick out still more.
However!! your body structure and musculature MAY be masking that a little. As I say, you look to have a very good shot, does it transfer to a shot without the trainer?. If so, I'd say your "good to go!!"
When I get to anchor, it feels as though I'm leaning against a wall with my back. As I expand and release, I just "lean on the wall harder." That is just a concept that seems to work for me. My string side shoulder blade (as far down as possible) presses harder and harder against the wall.
Arne