So, I have decided that theorycraft and myself will never mix. I don't like math anyway. I'm going to basically wait for someone else to do the math and make my decisions that way. Simple! (Hah!) Thankfully, WoWWiki supplies a lot of information so I have to do as little math as humanly possible.
As for the FSW/SI vs. Mixed Tier armor question... I decided to not go visit Mr. Boom, Doom, whatever, because my FSW/SI stuff isn't very well gemmed and I'm not about to sink a ton of money into gems, mainly because 1: I'm not that rich and 2: I'm not convinced enough that even though my DPS may go up, I'll lose too many other stats to make it worthwhile enough for my playstyle.
Instead, I leveled my mage to 36. (Somewhat boring. The most fun I had was when I solo'd the 'Forsaken Courier' and company.)
Then I logged in Kiya, my BM hunter, and said 'You know, I keep telling myself that since I hit 70, I haven't actually trained..', so I went to IF and trained. Then while I was just idly browsing in the LFG channel, someone advertised for a regular Sethekk. Since Kiya is almost entirely in greens, I looked and said 'oh, there's stuff in there for me', and said I'd go.
And I got a lesson in how you can turn a simple Sethekk Halls run (arguably one of the easiest of the Aunchindoun dungeons) into a 2 hour hell-fest.
Lesson 1: Don't inspect your tank. He's a paladin tank. They're all good! Ignore the fact that your pet has almost as much health as he does. It isn't important.
Lesson 2: Inspect your 'competition', the Marksman hunter. Inwardly cringe because they're decked out in blues and you're in mostly greens.
Lesson 3: Scream in party chat that you've been controlled by the totem and the other DPS has to take out the totem. It's a good way to stretch your vocal chords, because that's all it will accomplish. Eventually, that pesky totem will wear off.
Lesson 4: Don't insist on marking even though the leader of the group doesn't know what they're doing, isn't marking or using appropriate CC.
Lesson 5: Suggest to the paladin tank that they can pull faster, since you have two hunters and an ice mage and while after each fight, that 1/16th of mana ideally should be drunk away, it's really alright. Watch as your suggestion is either taken entirely wrong (see next lesson) or ignored (can we go NOW? How about now? Now please?... please?)
Lesson 6: Forget entirely that the tank so far has exhibited no signs of common sense and watch in dismay as he ignores your trapped bird (the single pull on the way to Syth) that you trapped so the group could move up safely, and without marking anything, shield pulls the next group of three.
Lesson 7: Watch in even more dismay as a "four-pull" as it now is, becomes wipe #1 because the ice-mage gets knocked back into the room and pulls a group of three, the totem (remember lesson 2?) takes over the other hunter who fears my pet into the two-pull guarding the boss room. (wipe 1)
Lesson 8: After returning and clearing what didn't die, don't bother eating or drinking, because the paladin will face pull Syth. (wipe 2)
Lesson 9: The words "The prophet's fear and spawn ghosts that you need to avoid, so pull back to fight them" apparently don't translate well. (wipe 3)
Lesson 11: The so-called competition doesn't need arrows. They can kill things with sheer good looks and elite speak.
Lesson 12: The competition also doesn't like the fact that you're doing 20% more damage than they are and doesn't understand that pet damage factors into damage-meters. Her meter counts her pet, but not mine. My meter counts my pet, but not hers. This is confusing.
Lesson 13: Needing to sleep and having no arrows, plus getting a drop off of the first boss, is a very good reason to say 'GTG, bye!'
Lesson 14: "I didn't realize the birds were hitting me when I pulled that group." is a common disease of some types of Paladins. As is wearing no pants. (He AFK'd to put on pants. I swear to God.) (wipe 4)
Lesson 15: Decide on a kill order in the room just before Ikiss. We didn't need one before.
Lesson 16: One-shotting Ikiss ... wait. That happened. Holy hell, it's a miracle!
On the plus side, I got a new ring for Kiya.