Bob, I have no experience or insight into restricted and unregistered stock for an IRS declaration.
Google [writing off for claiming a loss on restricted or unregistered Stock Certificates] does list many hits, but most seem to be business oriented so variations of the search string may obtain better results.
Google [stock attorney] list many, and most of their web sites includes upfront discussions that may include the topic you are interested in. Plus, some may allow you to ask a question for a free response that may lead to a low cost more detailed response that could satisfy your inquiry.
Its just my opinion, but my recent feedback from Juan Mendoza (Director and Chief Security Officer at Bourque Industries) has been positive in that Kryron is real and has this year shown positive results that will in 2016 result in product applications that will bring substantial revenues into Bourque Industries. Thus, my stand is to hold and recommend no one to consider any path for taking tax losses.
Juan is reachable using phone number and e-mail, as been posted many times on this board. All one needs to consider, as a possibility, is that he is truthful.
Doug