Creating the archings

I do prefer starting the rough arching before bringing the outline to a finish.
In this case, Douglas did a lot of rough arching because as my bump grow, so decrease my physical strength.
We don't forbid ourselves the use of machine tools in that process either as long as they are entirely controlled by hand, so the archings are still our creations.
When creating an arching, a number of material is at our disposal : templates, pictures, plaster casts (plaster copies of existing instruments - usually made by masters such as Stradivari), and for sure our experience is a good guide.
However I found myself that when I make an arching, my flair will be my best guide.