The changes discussed here address two aspects: a)
natives and population effects on colonial income and b)
a general increase in overseas provinces income. I will introduce this piece with a few considerations on vanilla mechanics:
Population normally determines production units, therefore production and trade income. Although an important exception is represented by overseas provinces whose production units will be always capped to one. We can infer that colonial population is completely irrelevant: tolls are absent, manpower is severely reduced and production units remain the same. It is useless to maximise population in overseas holdings, unless the prospect to link them to the mainland is a tangible possibility. In fact, population increases are even harmful, overseas when conversions are necessary.
Natives aggressiveness significantly lowers both colonisation chances and colonial growth. Exterminating natives (reducing their size to zero) voids these negative effects and represents thus the optimal choice under every circumstance. As is concluded above the population increase due to natives assimilation would bear no advantage whatsoever.
The mod allows colonies to feature more than the minimal one
production unit. Depending on population levels, up to 1.3 units can be produced the economic benefits of demographic growth and natives assimilation thus become discernible. In every overseas province counting more than 10,000 inhabitants a "Thriving Colony" modifier will be assigned, according to this plain table:
Additional production units are simulated via "trade worth" increments 10% representing 0.1 unit. Since the actual production base is always one overseas, "trade worth" effects are equivalent to increased production units. There are nonetheless exceptions to this similitude:
While supply would normally be affected by additional production units, raising trade worth percentages won't bear the same effect. It's useful to remember that trade goods supply determines their price. A "Thriving Colony" flag will accrue supply by 15% where population surpasses 10k: it is a median value, considering the rarity of 30k colonies. Provinces producing grain, wool, fur, or other trade good whose price is average or low, are not affected by supply increases the effects would be negligible, yet still computed and displayed.
Gold does not have a trade value. To simulate the effects of additional production units "local tariff efficiency" is used, in lieu of "trade worth". For every 10k population 12% local tariff efficiency is added, up to 36%. This number was chosen as it solves this equation for x
Tax base and tax income increases also determine production units in continental holdings. Since a) most colonies feature a low tax base and b) most Eastern provinces feature large populations, where tax base is high ... it's a fair approximation to exclusively consider population with regard to additional production units.
Population growth is relative to current population levels, it's a percentage. It goes without saying but, the higher the base, the higher the increase over a decade. A colony featuring 2500 settlers will grow faster than one with but 1000 people at more than double the rate with 10% decennial growth rates.
A coffee producing colony, featuring 30k inhabitants, will provide about one additional monthly ducat in the mod, compared to vanilla assuming a 25% tariff efficiency and 100% production efficiency (about seven ducats a year with a middle game production efficiency of 60%).
The same coffee producing colony will provide 1.3 monthly ducats more in the mod, compared to vanilla assuming a 75% tariff efficiency and 100% production efficiency. As with the above case we are negliging additional income stemming from centre of trade's activity the "thriving colony" will increase the coffee province's contribution to its trade centre by 18 ducats.
A gold producing colony, with but 10k inhabitants, will earn five more yearly ducats in the mod, compared to vanilla assuming a 25% global tariff efficiency. The same province with 30k settlers will earn eight more yearly ducats in the mod. With higher global tariff efficiency these numbers can even double.
In vanilla, Taiwan will produce as much as overseas Guangzhou: the difference in tariffs will stem from Guangzhou's higher tax base. In the mod though, Guangzhou's increased population will provide a distinctively higher income than newly settled Taiwan.
There now is an alternative to wiping out natives in provinces to be colonised: assimilation provides long term economic benefits, to be weighed against the risk of failing colonisation attempts and suffering from revolts or espionage actions ("Incite Natives").
Income from both colonies and other overseas provinces is now generally higher, the latter significantly so.