I think this should not be an issue. You should have an economy 100% independant from import WAYYY before the silver prices becomes a problem. Once you have your arsenal and 3 gunsmiths + supporting folks, the only thing useful stuff from europe are horses. And it just happens horses are extremely cheap.
You have to cut your expense to what you really need : 1 Early fisherman, 300 ish Early tools, 4 Lumberjacks, 2-3 Carpenters, 2-3 Blacksmith, 3 Gunsmith and 1 elder stateman.
The rest is all optional. It is extremely profitable to get your Ore Miners, farmers and fishermans from the native villages instead of buying them.
My point in all that, is the amount of money you need to get your colony running 100% is TONS less than the volume of goods you have to sell to make the prices of goods drop significantly. Any extra money after goes for cannon, horses and elder statemans.
Conclusion? Stop worrying about the prices of goods, arm those miners and fight.