Don't overthink it. You're not running a pirate simulator.
Calculate the amount of gold appropriate to the encounter, and tell them they find that much in goods - you can be a bit more poetic than that, of course, but describe amounts in values rather than weight, and just do enough research to roughly eyeball the size / weight if it becomes absolutely necessary (which it usually won't, at sea.)
When you want to have more wealth than that on a ship, put it in a form that's harder to sell, and make that a plot hook for an adventure - eg. illegal spices or somesuch that have to be smuggled into port.
Good idea. Didn't consider that. I'll have to increase it a bit. Gotta have some spending money for potions since there's no healer.
For I am a sinner in the hands of an angry god.
Bloody Mary, full of vodka, blessed are you among cocktails.
Pray for me now, at the hour of my death, which I hope is soon.