I find it odd that there is no money cost for making units, especially since the game calculate the amount of labour needed to making a unit. Surely, for your economic model to make sense, labour needs to have an associated money cost.
Labour wouldn't cost that much maybe, ten points of labour = 0.4 Gildar.
While your mechanic for upgrading units’ works fine, unfortunately the cost of actually upgrading a unit is astronomical. I had a unit of Spearman with leather armour: the cost of upgrading them to chain armour was over 5000 Gildar!
If we take the example of upgrading a unit from leather armour to chain armour, I propose that the cost should be the material need to make that much chain armours, and the cost of the labour needed to produce it.
