Help me with fire resist set please

I'm trying to gather a fire resist set, but I'm having some trouble since I don't have enough badges for the full epic set atm. Best I can do with what I have now and some crafting is http://wowdigger.com/character/view/18764#o6. I could switch the defence trinket for the 33(?) resi one instead for less crits but it would even futher lower my avoidance. If I get 25 more badges which I won't be able to right away, I can switch to normal gloves and belt and get the fire resist legs instead, but that won't really up my avoidance since I don't have an avoidance belt or gloves. :/ Would give me few hundred more hp tho. Next patch will be a nice hp boost, but I could use some hints about what I could possible change for a better result before I get more badge stuff and what I possible need more to be able to tank the fire elelementals at Illidan? Thanks for any ideas.

First, my general approach for deciding how to put together resistance sets:

1. Find out what kind of gear pieces are available.
2. Because maintaining defense is critical, I calculate a resist gained/def rating lost ratio for each slot to get an idea of which pieces give me the most bang for my buck. I also tried looking at resist/(def rating + stam difference), but the results were generally similar.
3. Based on 2, I came up with a gear set that would get me up to 295 unbuffed FR while sacrificing as little defense as possible.
4. I am a huge math nerd.

As far as conclusions go, I'm guessing that the gear set I came up with will be pretty close to what's optimal for anyone else, the resistance portion of the set is as follows:

badge chest + 15 resilience enchant
badge legs + nethercleft patch
badge hands + FR armor kit
badge feet + stam or stam/run speed enchant
TK attunement ring
SMV quest neck
level 66+ cloak "of Fire Protection" + 15 FR enchant

Total FR: 295-298 (depending on quality of cloak)

Remaining slots available:
Head
Shoulders
Bracers
Belt
1 Ring
2 Trinkets
Weapon/Shield/Libram

Recommended itemization for other slots:
Shield: S2 shield, hands down (or season 3 if you can pull it off )
Trinkets: the 2 highest defense trinkets you have available, there's also a 32 resilience trinket off of heroic Black Stalker

If you can't have a full epic FR set right away do what you can, but really: it's the last boss and you knew it was coming....there just isn't any excuse not to fully prepare yourself, to do otherwise is to hold your raid back.

I have an excuse! I have been holy for a very long time and we have been killing Illidan for over 3 months now. We have other tanks who can and have tanked the elementals but now it seems like I should gather a set anyway in case it's needed some time, which wasn't exactly expected. Anyway I guess I'll just wait and see, try to gather some mats for the blue stuff in case it's needed and once I'm less busy irl I can farm some more badges, from ZA next patch anyway.

Ah, that makes more sense. I'd still say that you shouldn't volunteer yourself on Illidan until you're top-notch, but your guild may be comfortable enough with the encounter that they've got some slack to give.