The Working Model
Strategic influence can come from many sources. If we understand the use of tanks in WW2 we see the best use was not to engage in tank to tank battle but to encircle, with artillery and infantry used to destroy enemy tanks. Interpreting what a tank equals in Utopia is not as simple as heavy attackers, but a concept of resource expenditure. Still, we know there were tank aces responsible for besting a great number of opposition tanks and we can interpret these in game as rovers. But I digress. The better way to approach this is to look at the actual generals available, army available, ops, sabotage and regard the occupying force of your enemy nw/acres/capability/resources as the encirclement objective. Thus, when you see an enemy t/m array you can't bite off more than you can chew and expect victory. You operate within these sectors with deliberate goals and exploit weaknesses to bring alternative logistics to engage.
I've learned to leave no one alone. As a heavy attacker I've dropped potshots on enemy faeries like Lightning Strike and time to time it gets through. If it gets through I follow up with selective ops and sabotage to probe for weakness.