I sort of like the " list 15 pins here, post pics once, set your nonnegotiable price" wash, rinse, repeat until gone. The fee you would pay here is way less than eBay, gives everyone a shot, and most likely your buyers are pretty legit ( compared to eBay CL stalkers). Just make sure the price is good for YOU.
After you run through the lot, call the truck guys for a bulk sale to end.
There will be hassles regardless...good luck, and hope you accomplish your goal.....