@Eudaemonia with regard to punching more per square than if you'd build regular residences/workshops/manus, in my city that is half the size (16 expansions) at the same chapter with a combination of very selected event buildings (5 at this time) and regular residences/workshops/manus, I achieve essentially the same results as you are describing (my tournament scores are only 1890 because I only have 7 provinces of each type open, strategically choosing to scout less and save provinces for events, and I usually don't go all the way through the laboratory in the Spire because my fellowship only gets a bronze medal).
I have slightly less manufactory production than you do, with only 8 level 9 marble, 4 level 3 marble, 3 level 10 crystal and 1 level 4 elixir manufactories, but I maintain a growing goods balance with 2-star trades. (My fellowship is not hot on the spire, but we have very active traders.) I produce a substantial surplus of coins and sufficient supplies.
In what way are you punching above your weight per square? And how would a chapter 3 mana sawmill help with that?