Stam vs Avoidance stacking...stumped

So i recently geared my pally and began tanking in a raid group in guild because the old MT left. Its been a few weeks now and obviously I have the gear to go either way with this and I'm really not sure which way I should. So right now I'm beginning to gem some stamina in as we are moving farther in our heroic progression (currently 4/8, attempting 5/8 tomorrow). I've looked around and haven't really found a straight answer to this. At what point does adding more dodge and parry become less useful to my healers than using those stats for stamina? I would think that since stamina doesn't actually help my healers out unless I'm dying it would be never, yet I see the pally tank in <vodka> on my server stacking stamina almost exclusively. I could understand if things in our progression were 2-3 shotting me but honestly the hardest hitting thing I deal with right now is probably void bolt stacking up to 7-8 on hc yorsahj and the shadow damage on hc zon'ozz but nothing is really killing me. I've asked my healers and they say my health pool is fine. So if I'm not dying and holding up progression should I stick to avoidance or is stam really better for some reason I'm not seeing?

Armory:
http://us.battle.net/wow/en/character/Alterac-Mountains/Swurvin/advanced

Also I'm over the ctc cap when raid buffed by what i've figured to be around 80 mastery...i can drop that i just wanna know if putting it plus more back into avoidance would be good or if some mechanics i have yet to encounter on warmaster/spine are gonna need me to have that extra stam. i figure i can add up to 27k hp unbuffed with a full swap in the way im gemming, but id lose 7-8% of my dodge parry to do it

You're going to find a lot of varying opinions when it comes to this regard. Neither is really better, per say, than the other if you are not dying. It's more about what you and your healers are comfortable with.

I personally have gone the route of 8% hit/26 exp in my standard tanking set.

Heavily influenced by Theck, I started going stam after having done as Fenrir for damage output. Basically, the dangerous things are unavoidable (and generally unblockable as well), so the only way to increase your resilience against them is stam.
That being said - apart from heroic madness (as I understand, we've stopped raiding and only got to 5/8 hc) the zone buff means you probably don't need stamina, and at this point I would definately go with hit/exp - not only for more reliable HP generation, but for more damage output.

So basically the answer is there is no answer...I can do what ever as long as my healers are ok with it. So the strategy for pally yearly is now cfc cap then gem something useful doesn't matter what?

Yes, generally speaking there is no exact right or wrong. However avoidance stacking isn't very effective for any of the current end game mechanics and gives no increase to DPS. It's decent on Blackhorn and blood tanking on Spine but that's about it. Although on both of those fights it's neither game breaking nor even necessary.

With stamina you get increased DPS through vengeance and increased survivability. With exp/hit you also get increased DPS and smoother holy power generation. Because you get dual benefits from both stam and expertise/hit you would probably be better off capping/stacking those instead of avoidance.

Avoidance is random, it could end up saving your healers some mana but more likely than not it will just add to their over heal amounts. With stam stacking your healers will be able to use more efficient heals without the fear of you up and killing over all of a sudden. You can't dodge Impale (or insert any one of the most dangerous spells/abilities in the tier here instead of Impale).

Edit: Stamina will also give your healers a larger cushion for mistakes theirs, yours and dpsers who may have stood in something they shouldn't have. Sure avoidance could do the same but it is not guaranteed like stamina.

Swurvin wrote:I would think that since stamina doesn't actually help my healers out unless I'm dying it would be never,

This is a pretty common misconception. Even if you're not dying very often, stamina can still help your healers. Let's try this analogy on for size:

Let's say you have a bank account, and your rent is automatically deducted from that account every month. You're trying to decide whether to spend some of your income on low-risk, low-reward lottery tickets. Those tickets might pay off, giving you 1/3 to 1/2 of your rent. Or they might not, leaving you with a little less in your account than rent. At that point, you'd have to divert funds from elsewhere to make sure you could pay rent - maybe cashing in some other investments, taking out a loan, pawning off something of value, or diverting funds from elsewhere (i.e. eat Ramen for a week). Most people would prefer the steady, reliable path of saving their money. That way, they have a bigger buffer when something bad happens (kids need braces, natural disaster destroys car/house, etc.).

Stamina is basically your bank account - by having a larger amount of health "in the bank," your healers have more time to react and can make better decisions. They can spare a GCD to save the DPS player that desperately needs a heal, they can use slower, more mana-efficient heals, and they can spend more attention in other places. They won't need to divert attention from elsewhere as often just to keep you alive, and they won't have to "cash in" on their bigger heals or cooldowns to save you as often.

And as others have mentioned, most of the dangerous sections of the later fights in heroic Dragon Soul ignore avoidance. They're rigged lotteries, in that you can't win. Impale, Tetanus, and everything else of note on Madness ignore avoidance. Bloods on spine don't really require avoidance if you're kiting them. Shockwave and Disrupting Shout on Blackhorn can't be avoided either. There's just no real incentive to stack avoidance for any of those fights.