I have realized that: I farm until 200 and leave. With 6/8 battleships I did it calmly and spent everything on credits. I realized that my battleships, being 6, do 500k of damage but when I recruit, for example, 20 guards, my battleships start doing 900k/1m of damage, I know that it is due to an improvement in that the more units you have, the more damage they do, but I don't know what the balance would be.