I make my database as I progress in the game. I make a new dungoen, I make the enemies, the troops, the new equipment, some skills to balance the gameplay better if necessary and test it all then. :3 I usually play the dungeon through a couple of times to see if it's too hard, too easy or just fine, Same with boss. I battle a new boss at least 5 times. If he's too hard, I consider making him weaker in some way. If he's ok, but has a weakpoint, I consider making the effect of the weakpoint milder so the player doesn't get a complete advantage when he discovers it.