I went back through my city and looked at the values of event buildings from the past 7 or 8 months, to see which chapter I was in when I won them, and came up with a rough number of 4 months, give or take a week, for me to do all of S&D. I upgraded the square to level 4 as quickly as I could and only built 3 of each school, upgrading them all to level 4. If I could have built 4 of each, I would have finished probably up to a month quicker, so maybe 3 months optimally to do the chapter. This was also without spending diamonds during the chapter and having little or none or the time reduction instants to speed things up.