Are there standard accepted definitions of these sections? Does the bass consist of only those strings that are above the others(overstrung) or is it all the wound strings? Where is the break between tenor and treble? I ususally think of the treble as being the upper two portions of the piano as defined by the divisions in the plate.

Really good question. As far as we tech guys are concerned, "bass" strings are the wound ones, wherever they are, and all others are "treble". It will be interesting to see what other folks' definitions are.....Sam