More to the point.

Murray,

Why would a hand made instrument proportionately see any more improvement (Difference) than a factory guitar?

The parts of a guitar that come into play are relatively the same.

I was going to raise the point that some pins actually do fasten down the string in a little different way. For instance, I was up at Elderly yesterday and a friend and I noticed that the string slot in front of the hole is considerably pronounced in the Gibsons I saw, whereas, the Martins, Collings, Bourgeouis, Larrivee's etc are essentially a string hole. the pin itself MUST be grooved in the one case, not so much in the other.

One might guess that with increasing age in the guitar (with the pin holes slowly but surely increasing in size), the hardness of the pin might matter less, as it does less "pinching" and more just holding in place.