I think it's possible since I lag on diplo tech and there are still many leaks, although AI can mess things up so we will see
BTW what was your naval force limit in your Spain game, I saw very small maintenance cost on your screenshot in Hall of Fame thread
Quality of ships matters, I waited for researching Heavy Frigate in my Hansa game before creating full route.
It's not Ivory Coast -> Mauritanian Coast -> Seville, it's Ivory Coast -> Timbuktu -> Tunis -> Genoa -> Seville - 4 nodes longer means that income in Seville alone can be 4.5 times larger than in Venice (9 times larger in Antwerpen - best spot ffor capital

)
1) I go Ivory>Timbuktu>Tunis>Genoa>Seville>Bordeaux>London>Antwerpen
2) I went there around 1650s (+- 20 years), I got china by diploanexing forced or released vassals for which I've conquered land.
3) I've started with Diplomacy and waged revolutionary wars on half of Europe

, after that I went after Exploration, Plurality. Rest is all other ideas from diplo group and Offensive. Now I'm thinking between Espionage and Quantity as last idea.
Just read this thread carefully from the beginning, it's not that long.