You can dimension your sketch using the "Fully Constrain Sketch" tool, available in the Sketch pop-up bar or in > Dimensioning Tool> "Constrain Sketch Entirely" (see IMAGE)
if you have to machine an artistic form, it will be done in CN. A simple and effective solution is to indicate that the machining will have to be done according to a digital file (a DXF scale 1 for example) that you attach in addition to your plan.
On the MEP you may put some dimensions so that your machinist gets a first idea.