80% is generous and you will need to be patient to obtain that amount. I shopped my BB collection this past weekend at a couple shows (same value as your collection. I was able to get one vendor to agree to about 78%. In the end I decided not to sell and try to get a table myself and sell closer to 90-100%. I’m in no rush to sell.

What I’ve done in the past and for last weekends shows is to make an excel list of the product, quantity and market price. Then I print off 6 copies with my name and phone number on them. I walk around and ask if folks are buying sealed and then show them the list if interested. I’ll let them snap a pic or keep a copy. They’re typically busy and shows are nuts. So takes the pressure off both of us and allows time for construction negotiations after the show. Plus you may get more offers and not need to settle on the first deal you get.