Ok, the wall boss, here's the scoop:
[spoiler]The first thing you need to know is RUN from the first one, and FIGHT the second one. This saves time and resources.
The trick to this guy is to keep the heat on. Always have someone attacking. Set your gambits so that when anyone is low on HP, anyone else can heal them.
The key to FFXII, though you may not yet know, is for ALL of your characters to have at least some healing power.
White magic is cheap in LP, and for less than 100 points you can have everything from Cure to Raise. That's a barigain if you ask me.
Back to the boss though... Keep attacking and keep healing. Phoenix Downs really come in handy here. Use any damage-dealing items you have early on.
DO NOT use your Quickenings at the very beginning. Try to get the boss down to 50% HP before initiating a huge chain of Quickenings on him.
If you are good and lucky, you should be able to get enough blasts in to take him out. If he isn't dead, make everyone attack relentlessly.
A problem may arise if he tries to petrify you. It will happen, so be prepared.
You should have purchased Stona for your white mage (scratch that... your WHOLE PARTY should be a white mage!) and if so, then that will work.
If not, I hope you have some gold needles. If you need to get one or more of these things, use the teleport crystal to jet back to Rabanastre and get them.
FYI, more teleport stones can be bought at the shops onboard airships. Hope this helps. [/spoiler]