Interesting post... I find that I get more buzzes with lighter gauge because I pluck/pull 'hard, same goes for the action, I don't like low action personally, because it requires a softer touch. It's a question of taste I'd say, I strung one of my bass with D'Addario EXL160 rounds (gauge .050, .0.70, .085, .105) which is stiffer next to the previous 100, 80, 60, 40, but I like it better with the heavier gauge, it does feel a bit strange at first, but then I prefer it, I get less buzz, more expression and speed, more bass obviously, a bit less treble as well.
I also have some TIs flats and they are really good, I like them and although they have a light tension, they don't buzz, next to a similar gauge rounds. I wish I had an extra set in fact.