hi welcome to the GMB - regret to say that it's very unlikely anyone will give you that sort of information via the GMB. There is occasionally a request to value a piece of glass, and for similar ethical/practical reasons we always decline - which may seem unhelpful, but is a necessity due to the range of values that different people will put on any given piece of glass.
It also avoids the obvious problem that if a value or cost is given which subsequently turns out disadvantageous to the buyer/seller, then arguments cannot ensue - very much hope you will understand, we are really not trying to be unhelpful - just avoiding problems.
It's always possible that one of the p/w collectors might give a guide to value, privately and off-Board............. it may however, be more useful if you look at on-line auction sites to see how these pieces have fared previously - real auction house may also have sold such pieces, and their on-line catalogues may give the information you seek.
Again, sorry to be negative - this is a standard reply, there is no discrimination to you personally.
