(..)Now my question though: How do I demand Bruhir to open their CoT to me? I do not see the option in the demand tribute list. The game itsself says I can open a CoT by both warfare and diplomacy, but I can't find it. The war is nowhere far enough progressed for me to demand anything, (4%+) but I find it strange I don't even see the option.
Then another question do spices become more valuable over time? ceylon and sumatra all produce this and historicly it was highly sought after, but so far the prize is 3 or something.
The first question I have no direct answer for, but when you vassalise the country, their CoT should be open for your traders.
As far as spices are concerned, their trade value increases over time with every town hall, cathedral, constable, treasury, market and customs house that is built somewhere on the planet. The mentioned buildings increase the demand of the good in their province, and once there exist more and more of them, the price of the good goes up.
Btw, the same is also true for ivory, tea and chinaware. For coffee, sugar, tobacco and cotton there are even more buildings (the naval buildings) that increase their demand.