With my warrior I had lots of mana from equipment bonuses, going with about 2 parts strength, 2 parts agility and 1 part constitution, on average (boosted constitution more earlier in the game, until it got high enough I was fine just relying on equipment for much of my hit points). Charms would have likely given plenty of mana for a battle mage, though I also built up many more restoration potions than I needed.

For a maximum, yes 90 should be fine. Just before fighting the Demon of Lies, my stats were as follows (the number in brackets indicates the values with no equipment, without Finnigan's lockpicks in my inventory).

Code
Level 53 Warrior

Vitality  1260 (444)
Magic      574  (30)

Strength     145 (111)
Agility      150 (112)
Intelligence  18 (10)
Constitution 100 (74)

Offense  124 (89)
Defense  108 (78)
Damage 139-178 (54-64)
Armour   484  (0)

Lightning Resistance 95 (25)
Fire Resistance     110 (25)
Poison Resistance    35 (25)
Spirit Resistance    95 (25)

Reputation 51
Weight   4500 (3820)


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