If the Cg is correct, and the airplane flys well, but still drops the tail on the ground, it's the location of the main gear that makes it do that. My son's Eagle 2 trainer is very light on the nose gear when sitting on the ground. It's a Good Thing! When nosedragger planes have the main gear too far back, the planes don't rotate on takeoff as well. They have to get going much faster to get that nose up. They also slam that nose gear down on landing. That's one reason why Hobbico and Tower trainers are substandard when compared to Trainers like the Sig and the Goldberg .
As far as the Tiger 2 goes, if it seems tail heavy on the ground but good in the air, bend your main gear back a tiny bit until the plane will just about balance on the main gear with a very slight preference toward the nose. It will rotatate and land like a dream.