Thanks for that summarization, Ah_dut I was too busy playing to take the time

A slight clarification of the mines info, if I could:

There are four types of mines, each of which makes a multiple of the lowest level one (Salt's 26):

Salt - 26
Copper - 52
Silver - 78
Gold - 104

All the mine complexes double the income of the regular mine, but cost less than twice as much. Thus, the first-level mines pay for themself in 10-14 years, and the second levels pay for themself in 16-18 years. I generally consider anything less than 20 years to be pretty good (whether farms, mines, or trade). But because salt and copper produce so little income in real terms, I often delay them, especially in provinces that have something else important going on, like developing trade and farms in Sweden before its copper.

Might I also point out a simple mnemonic for figuring amortization (pay-off) time here, and a modelled listing of every province's income from all sources, here (an Excel spreadsheet).