James,

I don't know of any way to get the maximum radius automatically, like the minimum radius. If you turn on the curvature comb for your spline you can at least find the area where the largest radius occurs. You could approximate the maxium radius by fitting a 3 point arc to your spline. The larger you zoom out the screen and the smaller the distance between the three points, the closer you will be to the theoretical radius, but it will always depend on how close your points match with the spline.

Jerry S.