These notes do not transact in the market very often if at all, so these are difficult to price.
The notes already book high starting at $250 in Unc, so if you use that as a base, I think you will be very close to an actual market selling price, and go from there to establish the grade of the note and set your sale price of the note.
The book is a guide, and is great for comparing like items from one series to another in the same price range.
You are right in saying it is worth what someone will pay for it, but I think that the $50-$100 might be a good estimate based on data known from like notes.