I think the above solution can work with other curves.
Lets try the same to one curve created with the two projections method.
First sketch one curve individually and then the second curve also, to another plane.
Create a two projections curve taking reference the two curves you have just created.
Now you have three curves. On the projected curve create a plane (you will use this plane later as sketching plane). Use Insert Datum Plane>Through> pick the projected curve > Done.
Create points again with the method LenghtRadio or Actual Len with the Insert Points > On curve, on the projected curve.
Now begin creating curve selecting the plane you have created above (through the curve) and select two points to take as reference for sketch (the points you created above). With the Use Edge command select the projected curve and trim the curve outside of the two points (if you have problem with that, sketch centerlines through the points. As the result you have a curve that connects the two points and similar to the projected curve.
Now pick the two curves you created first (those you use to make the projected) and change any dimension you want, change the value of the Length Radio or Actual Len (the option you use), of the points that drive the curve, and regenarate.
You can see that the curve stll connects the two points and it is similar to the projected curve.
As a result is that we have different curves between the points we want to have dimensions and the curves are taking reference these points and are similar to the projected curve.