thanks for contacting us. Please find attached an amended version of your file that improves the riser spacing. I haven't actually changed the RailClone object but instead I've adapted the base spline. In the original version the path was a flat half ellipse that was rotated, but actually it needs to be more of an S-curve in elevation view. This is to make sure that the rise stays constant for each step.
An extra tip, You may also find in future that you get better results by centring the treads to the spline on the Y axis. The will minimise the amount the moulding on the tread edges is deformed the further it is from the spline.
I hope that helps and that you enjoy using RailClone. Please let me know if you have any further questions. Many thanks!