Level 79 Priest Outfits: SP vs Mana Regen

Here are my four outfits on my level 79 priest, at the moment.
The horizontal axis is my mana regeneration unbuffed.
The vertical axis is my spell power unbuffed.
The numbers literally go off this chart when I'm in a GOOD group.

You might ask..."So??".
I answer: depending on the tank and the instance, I can choose to last forever tossing out low power heals, or heal hard and fast but need to drink more often.

I'd also like to thank the coolest page on the internet for generating this graph for me!: Wolfram Alpha

(Going from left to right using the names A,B,C,D)

Dot A: If the tank has terrible damage mitigation, and needs constant healing then I use this outfit:

( Pawn: v1: "Weighted": Intellect=2, CritRating=4, IsMail=-1000000, IsPlate=-1000000, IsLeather=-1000000, HasteRating=5, Spirit=3, SpellPower=6, IsShield=-1000000, Mp5=1 )

Dot B: If I'm going to take a lot of damage, or need a balanced spread all across the priest sprectrum, then I use this pawn scale:

( Pawn: v1: "OnePointPer": Intellect=1, Mp5=1, CritRating=1, HolySpellDamage=1, IsMail=-1000000, IsLeather=-1000000, HasteRating=1, Stamina=1, SpellPower=1, IsShield=-1000000, Spirit=1 )

Dot C: Just wearing the best items by Blizzard's default ItemLevel. I enchant the best mp5 or spellpower available to the item. This outfit tends to be used when I don't know the tank or the instance yet.

Dot D: If the tank moves fast through the instance and has decent damage mitigation, then I use this pawn scale so I can toss PwS and Renews all day long without slowing up the group to drink:

( Pawn: v1: "ManaRegen": Intellect=0.1597, IsPlate=-1000000, IsLeather=-1000000, IsMail=-1000000, Spirit=0.2432, Mp5=1, IsShield=-1000000 )