So if you take your collection to a dealer 55% is a fair offer from them... understand they have to make money on the transaction at some point.
You can sell on
ebay for around 13-15% fees.. but you will have to worry about shipping and such.. with your higher priced coins it's not bad if you have signed tracking ...
You could sell through an auction house... probably 20-30% of final hammer price will be the fee.
All I have to say is that from the pictures you have a very nice looking collection with some decent dates! That alone is something to be treasured..... good luck with the coins and thank you so much for sharing and putting up pictures.