Help with Tiffany value please

I’m hoping someone out there can help me in valuing these Tiffany pieces so I can make a fair and reasonable offer. The pieces are monogrammed and the coffee pot is inscribed 1882. The creamer and sugar are inscribed 1910. The photos show hallmarks on the coffee pot (5362M5261) and the other hallmarks are on the creamer and sugar. They weigh a combined 940 grams. Any help is appreciated. Thanks

Generally Tiffany pieces carry a substantial premium, you might look on eBay’s sold items for Tiffany coffee/tea sets for ideas of what price you should offer.