Create a Datum CSYS.
Create a sketch on one of the planes of the CSYS consiting of a line (horizonal) and a spline of the shape you want starting at one end of the line and ending at the other.
Add Uniform Scale constraint to the spline.
Either dimension on line or fix one end of line.
Can change the scale of the spline by changing length of the line in the sketch.
Can change the possion by moving the Datum CSYS.
Can create another by copy and pasteing the sketch to another CSYS.
Hi, @StevenVickers Thanks for your reply!
Spline in sketch can have two types of constraints: Non-uniform Scale and Uniform Scale.
Both of them don't allow scaling in X direction by factor A and in Y direction by factor B at the same time.
I'm not sure whether I missed something important.