There is a very easy solution to this one, once someone’s shown it to you…
My labels don’t correspond to yours, I just grabbed a random pattern to explain.
Pick up the Point - Intersect Arc and Line tool, select the 1st point on the line, in my case it’s A15, and then the 2nd point on the line, mine is A16. Then select the neck side node (A10) as the centre of the arc. Enter the formula “Shoulder length + 1” and click on OK.