This is one of the most difficult positions to get correct and we do a ton of them in the ashtanga system. So that's a good reason to take more time to figure it out. These are just a couple of little projects to bring more awareness to the activities needed to do Up Dog without compressing the back and to stay strong and stable! In person we can help you more, so come to practice!
By the way, in this photo, my shoulder blades are a bit too close together, the project is also to separate them. In the video you'll see better that they also do separate and the end tip slides more to the side front body.