You can cheat on Joiplay if you need.
For a mage I would equip Cloak of Speed, Adamantite Helmet, Warlock's Ring and Amulet of Mana. You can also trade 10 max HP for 20 max MP indefinitely at the Academy of Magic, so between HP and MP, HP it's always better. At the statue in the beginning you can gain 50 max HP (equals 100 max MP later), after finishing the quest at the cemetery you can also choose between a potion that expands you MP by 50 or your HP by 100 (this can become 200 max MP at the academy). With 750 max MP and Amulet of Mana, you regen 75 MP every turn, making the battles a lot more manageable.