Nice overview!
I also did this calculations. For me the most important parameter is your "total cost per capacity".
It shows how often a unit has to bring loot at home until it paid itself. These factors are to big! Considering high costs per unit and that you have to built up a huge army it makes no sense to waste resources on units.
I recommend to build up more storage instead.

P.S.: I made the experience that in case of being attacked the attack value of the defending units is compared to the defense value of attacking units. Hence Bazooka Guy and Sniper are the best defending units.