Project - Time wars

Hey, my new game is called time wars. Believe it or not, I thought it up during church, my mind kinda wanders when I'm bored. Anyway, the idea is that you choose your hero and send guys to your oppoenent, who in turn is doing the same. As long as there are guys in your "arena" your time is constantly decreasing. Your income is how much time you have left. So sending units increases your time, which in turn increases your income. You lose when your time runs out. I need your opions on varibles, like how much your time should start out as. I have all the