Spline point max rotation

I’ve been trying to make a script for a train track spline that can be moved and edited in game. I add a point to the end of the spline when clicked and set that to follow the view point until clicked again… easy stuff
I’m however struggling with how to set a max rotation on the spline, ie I only want to be able to place a point at a max 45 degree angle from the last point. I’ve tried so many ways of doing this and come very close but it’s somehow alluding me.
Problem being that the world rotation of the spline is giving me figures ranging from -360 to 360. I can’t figure this out so any help would be appreciated.