5:43 PM, Wednesday July 22nd 2020
I think you are over thinking the shoulder part. As long as the elbow is not on the table and not restricting your shoulder, a strait line is a combination of the movement of the elbow and the shoulder. The wrist shouldn't do much though. Don't go locking in your elbow and making your arm stiff. After that, focus on making a strait line, and your body will do the rest. I hope that helps you