I just tried it, heres what I got:
Tuskens: I didn't win this one, the Jawas were two points ahead of me each time. At first I tried to used the infantry Tusken, but I couldn't kill the Jawas off fast enough. Sniping them off from the top is the strategy that worked best, because they seem to expose themselves very easily. It just wasn't enough to win though.
CIS: The key to winning against the Gungans is to kill them before they kill your men. Run out there in the middle of the fight, and slaughter them down before they get a chance to throw those grenades. Keeping your men alive is the main objective.
Empire: I have no idea why you're having problems with this one. I only lost three men, and two of them were by friendly fire. I didn't die once. The Ewoks didn't even fight back for the most part. Just charge at them and mow them down, keep moving so they cant throw their rocks at you.
Hope I could help.