Can't say that I know about those tools. What I always do working with 3dsMax is I have a seperate object I use for spline generation. The reason for this is that I can import it seperately and have a seperate geometry.ini for it including just that object and the sky. Also you can change resolution between the spline and visual mesh, spline needing less polygons to drive well vs the visual that needs more polygons to look good, especially in corners. Additionally, when the only objects in your scene are a spline object and the sky, automatic spline generation will almost always work, even with cross-sections