I think the initial version without building the resource silo was better. The Capitol will still be built on day 212, but we save money, and we'll have enough wood to upgrade the Gnolls, Lizards, and Flies anyway. Upgrading the rest isn't necessary. While we're dealing with the Swamp, the Barbarians will have completely rebuilt our starting Castle and even added Hydras! The Hydras are useless, but that's beside the point. :
By the way, the screenshot shows how we managed to save Gnolls on day 133 by using Snakes as bait. However, this also creates further logistical problems – the movement point costs for support units. When there are only 2 active heroes for tasks in the Swamp (the third hero has their own tasks far away), these movement points can be critical.
PS, all this talk has motivated me – I'm going to make a little more progress in the walkthrough