We have tried a new experiment, we tried to reach the crystal level with only using the popular barch strategy.
We got attacked 1 time resulting in a win of 8 trophies. We did fail 1 time during an attack resulting in the loss of 13 trophies.
It took us a total of 24 attacks to get the 103 needed trophies. During this attacks we gained 1.500.000 resources.
This mixed army takes 19 minutes to train, allowing you to attack 3 times per hour. It is possible to gain 100+ trophies per 8 hours with this trategy.
When you hit the crystal division you get the achievement League All-Star which gives you 100 x experience and 250 gems!