In my continuing quest to get a supremely bad repuation despite being a nice guy whenever possible (sometimes picking on people who attacked me), I want to vassalize Austria. They have formed a very large empire, larger by at least 50% than it was historically (let's just say that Peter the Great... wasn't). What factors affect vassalization? High relations, obviously, and you need an alliance and RM. But does having troops on their soil help, too? Will having good relations with other alliance members help?