Anyone know the formula for Spirit regen?

[TheWesson]

The forumla for priests is :

mana regen/tick = (spirit/4)+13

A tick is every two seconds, and is serverside, not clientside.

For other caster classes, including mages, shaman, and paladins (I believe):

mana regen/tick = (spirit/4)+x

For druids:

mana regen/tick = (spirit/5)+x

I believe health regen is around spirit/10 or spirit/9 plus a constant.  Not really sure.
[right][snapback]73112[/snapback][/right]

The easiest way to remember this is that one Spirit @ 2 min (of not casting) = 1 Int, for casters except Druids. (Druids are slightly worse.) Comes out to 1/8 of mana per spirit per second.

Some talents give 15% mana regen while casting.

...

So I'd really like to chain cast indefinitely. I'm shooting for 100 mana regen per second, while casting, and I have this awesome talent for 15% regen ... how much spirit do I need?

100 = Spirit * 15/100 * 1/8
Spirit = 100 * 100 * 8 / 15
Spirit = 5333

Okay, I'm going to make an awesome Mage build with 5333 Spirit who can cast forever. I'm only going to need to find 177 +30 Spi items to put on my body someplace. Shouldn't be too hard.

With my Priest, I have the awesome +35 Spirit buff, so I only need to find and put on about 176 +30 Spi items.

Aww ... I'm totally exaggerating here ... I'd still be pretty powerful with 50 mana regen/sec during casting. Besides, I have >50 base Spirit. So really I only need about 80 +30 Spi items. If I find them, and Blizzard adds about 65 more slots on my body, I'll be all set.

Summary:
As a guesstimate, 80 mega-Spirit (+30) items would allow me to effectively double my mana pool while casting.