Here's a spreadsheet I use to find profitable trade routes. No idea if its useful to other people but feel free to take a copy and use it if you want:
https://docs.google.com/spreadsheet...7mKoiHvWKOLUE9C0NUa74uvC7g/edit#gid=735743384
https://docs.google.com/spreadsheet...7mKoiHvWKOLUE9C0NUa74uvC7g/edit#gid=735743384