Most of the time I don't even bother with missions, cause I don't find converts that useful and even if you get that other guy that turns them into colonists, they still keep coming from the village with a mission afterwards.
I never thought of making 'mobile silver mining camps'. Not a bad idea, although unless I'm playing with the Dutch, price of silver usually drops down to 1 long before I exhaust the mine (maybe one of less realistic parts of the game, considering that price of ore never drops as fast as silver).
I'm quite mean to other European powers. I buy a privateer as soon as I can and then pester their poor ships as soon as they arrive to the New World, not even letting them unload new colonists (by which time I have already conquered their existing colonies). And because of the way the game works, they always arrive on the same spot, so you can set up a nice ambush. Then when I need extra colonists, I bring my dragoons and let the ship unload their colonists, so I could capture them.
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