Great question  Dave ,

I think if you took the top off of a master 's violin , built by him alone , and checked plate thickness graduation with calipers you could expect to see time and effort well spent ....The master also gets the best aged highly figured woods from his shop ...folks pay extra for that as well as the masters time ..and name ..

Violins made by many workers under the masters eye may show a degree of variance per worker but i would expect they too would be of good workmanship or they wouldn't be employed there in the first place ...also may depend on how close an eye the master has time for and how much the employees are on their own ...

In the end the sound and playablility along with the finish determine whether it leaves the shop ...

I have seen and played a few violins built by respected Master builders and their shops and have found some from each that were great and not so great sounding ..along with building flaws that i wouldn't want as well ...

There are differences in how a scroll is carved that will show a proper masters hand even if it may not effect the tone ... F hole size and shape as well as location is another factor as well .

Looking for value down the line , a Masters name , built by him alone , may be needed ....but even that is no assurance  ...

It's well known that some original Strads don't sound all that great ....see my post on violin scans ...

Once in a while a 3/4 German no name violin will turn up that blows everything out of the water ....

So , tell me ...what's in yer wallet ?