OpenRA

The current HP on the cards is 1000 because this stops them from getting killed even at the right angle of airstrikes (airstrikes do more damage when they come from a specific direction).

I think you almost don't need to add any more money to the oil if you buff the HP and give it a minor refund when engineers use it. (need to make sure its not when engineers repair it either).

Recapture will also nice for long games.

The health buff and refund are good. I would suggest that only neutral buildings trigger the refund. Recapture can go either way.

Ive been on and off with the refund using first time captures. Ive done 500 to 250. Still testing around with this idea. But the main is HP buff for certain.

The recapture as mentioned also applies to hospitals and other buildings.