Personally, tanking heroics has been a big hurdle to try to get over, and quite frankly I still am not even THINKING of stepping into some heroics.
I have roughly 13.5k life unbuffed and to be honest, getting above 13k life has GREATLY opened heroic tanking options. Heroic mobs just hit too hard to be risking a smaller life total.
If you are at 10k, you are too low. Its possible to hit around 11.5-12k without getting extremely difficult loot pieces and in heroics, since you can't get crushed, its generally ok to sacrifice avoidance in place for stamina instead.
When I was at 11.5k, I was tanking Heroic Mech and Heroic SP without much difficulty.
Now that I have 13.5k life or so, I've braved Ramps, Blood Furnace and Botanica. I have yet to jump into heroic Mana Tombs or Slabs because I hear, the boss fights are quite difficult. (although I think I'm gonna give it a shot this week)
I assume you are trying to get the badges for the libram of repentance and for possible 2.3 loot. If so, fastest way for me was to do two things:
1)Run H Mech everyday. (with locks and interrupts, this instance is VERY EASY) Also, by running this u build up the rep for exalted with shatar (for the shield) and u farm up Sun Eater (drop only in heroic mech and while not necessarily a good pally tanking sword, it does have nice defensive stats if you can allow a lack of spell damage)
2)Get on runs that have Kara on farm. (its 22 badges, PLUS some ok tanking loots. Definitely upgrades from those that you probably have.) While you won't be main tank, there is nothign wrong with tanking trash.
After looking at your gear, I can't really say that those slots aren't optimized, honestly, I think farming normal SV or heroic (if u can manage) is good because its fairly fast and you not only get rep for the nice neck piece, but u get a chance at a REALLY good back piece in the devilshark cape.
I wouldn't worry too much about gemming for avoidance right now. 120life per solid star i think is more important for heroics as of your gear now. I think one piece of gear that is GODLIKE and is fairly easy to get is Figurine of the Colossus from SHattered HAlls. SHattered HAlls normal is cake for a Tankadin and the avoidance bonus from the trinket is really awesome.
Just some ideas.