myself, buyer, taking risk. franken watch that is valuable, I just want to make sure it gets to me in one piece! ha
My suggestion may not be for everyone, but that's what I would do to avoid customs issue. I learned it from couple TDs.
If it is a 'used' or 'pre-worn' watch (s/h), then why not declare it as a watch being returned after servicing or repair, at a value that both parties are happy with...and then have it sent tracked and insured?