A Fortress, Stronghold, and Castle should not be built before 2-3 weeks – it’s too expensive in terms of money and resources. Sometimes, a Fortress is built from the start, in which case you can also build a Stronghold, which provides a +50% growth bonus, but again – it probably doesn’t make sense to do so before 2 weeks.
It’s very good if you can place Colossi by the end of the 2nd week. Then the growth will start accumulating, and you, in turn, will accumulate gems for their further upgrade.
So, is it expensive to build a Fortress, Stronghold, and Castle, but not expensive to have Colossi by the second week?
I don’t want to argue; maybe it really is more profitable this way, but isn’t 3-4 extra Titans better than 2-3 growth doublings?
(because after building the Colossi, not much money will be left, and the construction of the Stronghold and Castle will be postponed even further?)