One of my advisors died, so I hired a navigator and now I've colonised the Javan provinces (those I didn't conquer, that is), and... Taiwan. I've open markets with the Ming, so now I can place merchants in Nanjing, the most prosperous center of trade that I know of.
And I can also get another national idea! I noticed my tariff efficiency is only 57% (so I'm losing about 5% of my monthly income). I could go for Grand Navy and build more ships, so I could get my tariff efficiency up. Or I could ignore tariffs and go for direct trade, so that'd mean Shrewd Commercial Practices. Or perhaps something like Viceroys? Suggestions are welcome.
Have a look at my economy tab:
