I have been playing Col2 since it came out and have not found any way to avoid paying tax
The best you can do is minimize it by limiting trade with Europe. Tax increases are generated by the volume of goods traded in Europe (not the value) so one thing you can do is make your own tools in your colonies instead of being lured into buying those cheap tools in Europe.
There is most probably a way of changing the XML code to avoid tax but I can't help you there. Ask that question in the Col2 forums.
I have experimented with limiting tax increases. It seems to work, I've managed in some games to keep a 0% tax rate past turn 100.
- Never export goods to Europe.
- Never buy goods in Europe.
- Sell finished goods (cigars, rum, cloth, coats, tools or guns) to native tribes.
- Transform all raw materials into finished goods, or just let them go to waste.
Generally, at some point, often when I've got several galleon loads of silver ready, I go ahead and ship massively to Europe. Tax rates will rise quickly, and once they get to high I go back to selling to natives. In vanilla Civ4Col, the natives' resources seem rather limited, and they run out of cash. In Dale's AoD2 mod, they seem to be able to buy unlimited amounts, as long as you shop around and sell to many different tribes.
I have found it pretty simple to keep tabs on taxes, dont trade often and to begin with, do it with natives if possible... Now later with more ships, then fill ships, move them to natives if bedst income or to europa, but dont sell anything, just leave them there until all ships are ready to sell at both natives and europa, then sell everything and then buy new stuff from europa and move it back to colonies...
this i have found, means you get a single tax increase not long time afterwards, but you could have made like 10k 50k or even 100k, depending on production and ships...
i tend to go independent around 50% tax, which then drop to 25% and if you win disappear, but even with 25% selling to natives might give you loads of money still, so bedst option.