I will give some advices about your other issues.
1.Mana regenerates much faster if character is resting instead of working. You can also take succubus class to drain mana once a day or get lot's of experience.
2.You can create master with all factor mastered. You can pay your experience to increase them later.
3.Amulet is ok, but you can ignore it. It doesn't give you that much.