A few pictures will tell more than a thousand words, I only have to code it first. Then I will show better what I mean.
Actually it is easy to match both. The slope is allways matched by simply rotating the clothoid - it doesn't matter where it starts. Curvature increases linearly along its length so it's all about finding the right point.Don't the two curves have to match slope, not curvature? With slope only A works.