Just wait until you get past the first two limit breaks and see how much the juice bar requires for you to level up lol. Weapon Mastery is practically useless in this Disgaea. Also SP is not unlimited, once you level up your skills in the skill shop it uses a LOT of sp. The only thing that really matters in the juice bar is class mastery to unlock evilities. Also if you increase a stat by a single stat 255 times you can easily unlock the first stat break after reincarnating. Watch my early game leveling video. Extract farming is done post rakshasa V. Your characters max at 500b per character per stat. Good Video