Personally, I don't think Mana should ever regenerate unless you sleep or rest. Then again, I feel the same way about Health. No potion, no bed, no regen. I am amazed that it even regenerates at all in battle.
Playing a Pure Mage in Daggerfall was practically impossible because of the lack of Magicka regeneration outside of sleep, unless you abused the hell out of the bug where you went to use an enchanted item, then canceled it to gain magicka equivalent to the cost of the last spell you cast. If you tried to sleep in a dungeon to regain Magicka, alot of the time your sleep would be interrupted by a monster and you wouldn't have enough magicka to kill them. Potions as a whole in Daggerfall were rather rare.
In Morrowind, it made playing a Mage slow as hell, you constantly had to sleep or chug potions to go just a bit further in a dungeon.
Magicka School Reduction is nice and all, but you can only get 2 schools down to -100% cost though (Unless you use the Resto Glitch). I wonder how good dual enchanting Fortify Magicka with Fortify Magicka Regeneration would work, considering you regenerate a percentage of your Maximum Magicka per second (Normally 3% of total Magicka per sec outside of combat, 1% in combat).
It's a lame thing beth did to slow regen during combat as magic is a mages life blood. Just one of many ways they hinder the mage in skyrim.. Forget about magic regen enchants, your best bet is to enchant fortify magic and work on boosting your total magic...mine's at 1000 now and many spells don't dent my magic bar, i usually have enough magic to finish fights without recharging with potions
In your case, just from the Maximum Magicka you have, you'd be regenerating 30 Magicka per second out of combat, and 10 Magicka per second in combat. With the maximum amount of Magicka Regeneration from equipment (Without Resto Glitch), which is 375%, you'd be regenerating 112.5 Magicka per second out of combat, and 37.5 Magicka per second in combat. This is without +100% Magicka Regen from Apprentice Stone, +25% Magicka Regen from Elsweyr Fondue or +Magicka Regeneration from Potions either. Personally though, i wouldn't really recommend the Apprentice Stone, since it's 100% Weakness to Magicka can never be fully compensated, since Resist Magic caps out at 85%.