My colonial empire consisted of the southern half of the continent of Africa, the western half of Australia, and a Central American empire reaching from Florida to Peru, and from Venezuela to Mexico, including all of the Caribbean. I used to Columbian Exchange event to bring maize, potatoes, chilis and tobacco to Europe, and cocoa to Africa. I found out that the trick is to use Divert Trade from your colonial nations, giving you half of their trade advantage and capacity. Once Europe starts needing all those colonial goods, having the best trade advantage in all your colonial markets enables huge profits.

What I found disappointing was that without control over a market, trade doesn't really work all that well. I never managed to trade spices or tea from Asia, as I didn't conquer anything there. Especially tea was weird, as producing countries like China only produced enough of it for their own population needs. There was simply zero tea in any European market, despite the English actually having a "teatime" additional need in their country. With zero supply, I don't know how such a need would have historically developed.

Trade profit breaks the game, as cost in your economy are calculated on your tax base, not your overall income. I was able to manage to avoid the revolutions of the Age of Revolution by simply not taxing my commoners and burghers, and still had excess money. And I was able to put all expense sliders to maximum expenses, being able to afford a much bigger army and navy than my population would suggest. Although I never conquered much land in Europe, I ended up as a great power, and hegemon in multiple areas. So I stopped playing out of boredom. And I am not immediately going to start another game.