I've looked it over. If you don't mind, I'll comment on your idea, and perhaps you can add something else.

The mathematical sum of parameters doesn't always make sense. For example, the sum of HP for all units without considering the number of units of each type (which is what you're considering) doesn't make sense in terms of comparing cities. Also, the amount of gold needed to buy a week's worth of units should take into account the number of units. After that, you can introduce a parameter like the price of one unit of HP per week. To do this, you need to divide the cost of a week's worth of units, expressed in gold, by the sum of the weekly HP increase.

And based on this parameter, you can correctly compare all cities. But comparing the sum of unit speeds, as you suggest, doesn't give you any food for thought.

In other words, the numbers you've proposed don't have any physical meaning, and therefore won't be useful for Physics. :) I hope you understand my position.