To find Magus' best equipment, simply go to ozzie's fort. When you enter a room where he tempts you to take a treasure, ignore him and leave the room from the upper exit. Right when you're about to exit, he gives up and you're free to steal the treasure. Below the upper exit is a hole in the wall that you can't see. Walk all the way down and take a weapon, helm, and armor for magus. There should also be a magic tab in the same area.