Have been playing the demo as Portugal, and my overall trading strategy is to open my path to India. I managed to conquer and colonize bits along the African coast line (5 provinces in Congo, 2 provinces in Cape, St. Helena, Mauritius) and sailed to India. Then I start to wonder the optimal placement of merchants for best trade income. Particularly, the problem lies in the ivory coast. Should I collect trade there, or transfer the trade downstream to my home node of Sevilla? I think there may be bonuses for carrying the trade forward, but the competition of Sevilla is severe, and I only managed to get ~40% of the share.