Hi mat, I'd probably start by making a rectangle and type in your desired width and height for that so those are set. Then draw arcs on the ends, snap the center point of the arc onto the midpoint of the rectangle's end, snap the end points of the arc on to the corners of the rectangle. So now you have an arc on the end of your rectangle. Drag the arc by its midpoint and release it on the midpoint of the rectangle's end.

Now you can delete the rectangle, put in 2 lines connecting the arcs and you should have a lozenge created of your desired width and height like this:



If that works for getting the profile and width and height sizes that you require, then the next steps after that might be something like turn on control points for the lines and move them in a side view to form one step of a coil. The goal will be to make a path curve that you can then use Construct > Sweep to sweep a circle curve around to make the final shape.

- Michael