I have rephrased the question.
My game allows players to place new units. And to be able to place a new unit, you need sufficient factories.
It is a matter of counting. If you don't have enough factories. A big tank can't be placed.
I am looking for a good mechanic that will allow players to build big tanks with fewer factories. But I want to prevent chaos in the placement phase of the game.
Has any one an idea?
I think I have thought of a very simple solution this time.
I am not to happy about it. But it actually suits the game the most.
XP can be used to upgrade any thing. This includes production facilities.
But this time, I allow players to choose between XP and money. IF they want to increase their Building Points on any factory. It is very expensive at the moment. But more of that in another topic.