Still too short to be worn casually but I suppose that's preference. Definitely need to relax or lower the armhole depth some or increase the chest of the shirt. Maybe a little of both. Sleeves that are slimmed require a higher armhole and therefore maybe harder to slim without the pulling effect across the chest.
Can luxire adjust for posture? If so, that needs to be correct. Something else you can do is take a measurement of your fullback from one armpit to the other. Add a little for ease since you're going no pleats and that would clean up across the back. Depending on how you stand or how much "shape" there is between your waist and hips will/should also factor into how long you get the shirt made and perhaps what has to be done to it on the back end. Shirts shouldn't have excessively curved side seams because it takes the fabric off grain and creates a lot of distortion. To counter this or adjust for more "shape" or closely fitted shirts for the slim/modern trend, darts need to be added. Personally, I add them myself and I do it right behind or in front of the side seams so that the natural size of my arm tends to hide the the dart from view.
Can you describe more by what you mean by taking fabric off the grain in more layman terms? I'm also in the process of trying to get a closer fit to reduce billowing when tucked and trying to understand these two methods.