If you're trying to create an empire-wide overview map why not use the flying camera, toggle on bare map (CTRL+B) to light everything up, and take the screenshot that way (Windows' snippingtool is my tool of choice to grab/crop in one go)? It seems like using Hugin to do it will create a giant screenshot that will most likely crash my ancient cell phone browser.

Played: Pitboss 18 - Kublai Khan of Germany Somalia | Pitboss 11 - De Gaulle of Byzantium | Pitboss 8 - Churchill of Portugal | PB7 - Mao of Native America | PBEM29 Greens - Mao of Babylon