I am nowhere near there, but I have been spamming the 104 oil crusades fields. Some things i've noticed- I can kill it using only 3 tanks. I can also kill it under "auto attack" if i WATCH the battle. If I leave the battle in another tab (to see this forum, to play another game, etc) I can lose all my tanks if I don't switch back fast enough. Also, while my level 26 lieutenant does 42 damage a shot (regular attack, sometimes 84, which i figure is a crit), the level 15 opponent does between 64 to 85 in regular hits.