Help with creating sloped surface


I am trying to create a ramp from one elevation to another. I have the boundaries of the ramp. I have tried a few different methods including rebuilding the curves using a series to subtract from the curve z values, and then lofting, but this resulted in sections that were too sloped to either side. So I took one curve and offset it, but the loft outcome still has a weird bend in the profile in some locations.

I have tried patch but the outcome isn’t good and doesn’t really go through the boundary curves:

If anybody has experience doing more complex ramps like this I would really appreciate some help. I have internalized and shared the script below (24.0 KB)

Use sweep 2, and use multiple sections (15.9 KB)