In what way is the current calculation less than desirable?
he did some kind of brute force try and retry if the length fits, instead of calculating it... even if he is doing some kind of devide and conquer it would be nicer. I'm not shure if the calulation costs more, if we are calculating it with a circle intersecting the line (and taking the closer point to the given point).
If a garment doesn't fit the shoulders, it doesn't fit.
Proportions & estimates should be avoided if the measurement is available,
and shoulder length is one of the basic measurements so it's always
Maybe I was not clear enough: He calculates the correct coordinates, but the way to the result isn't very elegant. Anyway this is a pure coding issue, nothing to do with the fitting of garnments in the direct meaning. (I needed this kind of calculation in one of my last years patterns too, but sadly I can't find it right now. So this tool has the right to exist at least for me ;) )