Okay, yeah. EinBein didn't leave much room for anyone else to guess. What can I say? His reasoning is solid. Except...
Except for the volume.
The "bit of extra volume" between the coins due the gaps adds a whopping 75% to the overall volume when talking about larger amount of coin. So, that one liter chest would have been too small to fit 4000 coins. 3000 would fit in it with a very small amount of space left over, but not 4000.
Surprisingly, he did get another thing right that he probably didn't even think of -- the standard gold coin in 'Bastards is indeed called a Gulden
The Gulden in 'Bastards weighs 4 grams, having the average weight of a Roman solidus, weighing 4.5 grams, and a Florentine florin, weighing 3.5 grams. Florins weren't nearly as widespread as solidi, but over a hundred other states and cities took upon themselves to copy their form and weight when minting gold currency of their own, making it the closest thing there was to a standard gold coin after the fall of Rome. From the looks of it, the Bohemian Gulden was probably a Florin derivative as well.
So, the answer I was looking for was the one that 'Bastards wealth chapter would have given you -- 4000 gold coins would roughly take up 1.5 liters/quarts in volume, and weigh 16 kg or around 35 lb
