the large was appraised at $260,000 and we won't take anything under $200,000. the 5 carat studs are $35,000
That sounds about right for 5 carat studs. They would definitely be interested. Also, have you tried Bonham`s (I recommend

)Sotheby`s or Christies? You would have that thing sold relatively fast that way. I am not sure how much the fees are, but I think they run in their shows until it sells at your reserve.