I used a slightly different macro system for ease, thought it might help, I've posted this to other threads too, if you've already read it feel free to skip.
Well, after a dozen or so tries I'm suddenly having a whole lot of success. When I tried to figure out why, I realized that knowing how the fight would go wasn't enough, the key was in the macros, so i'll tell you what I'm using, maybe it will help somebody else out there, I know it's made all the difference for me.
First, I should say that I have subscribed to the "crack" method, and is the basis for my first casting of Carbuncle. Outside the crystal I cast Aquaveil, and use a fish mithkabob. I then enter the crystal, and run to the "crack", where I use my first macro:
/ma "Carbuncle" <me>
When Carbuncle attacks the avatar I then cast my second macro which I have named "Start":
/item "Yagudo Drink" <me>
/wait 5
/ja "Astral Flow" <me>
/wait 5
/pet "Searing Light" <bt>
Doing the two macros here assures me that carbuncle has engaged the avatar, and that I am not in danger. It also assures the quickest use of the first searing light so I can get off three before my yag drink or 2 hour wear off.
After Carbuncle has jumped in the air, I take off for the other side. When I reach the other side, and Carb has been defeated, I cast my next macro, "Carb2":
/ma "Carbuncle" <me>
/wait 7
/item "Ether" <me>
You may wonder why I didn't tack a searing light on here. It's because the time between summons varies. The avatar can take longer at times to kill Carb, so this gives the flexibility of the trigger in my own hands. Of very special note, I had trouble timing the second and third searing lights, but finally figured it to be when carb had been recasted, my ether had kicked in and my mp reached 55. That represents exactly one minute (2 mp/3 sec=40mp/min regenerated. Include -5 mp for casting Carb, then add 20 for ether= 55 mp). When it reaches 55 I use my "Sear" macro:
/pet "Searing Light" <bt>
After getting off my second sear I return to the top, and recast Carb2, followed by Sear. The only other advice I have is to make sure you have stopped running before hitting "carb2". Too many times I lost a fight I should have won because I made that mistake. Other than those specifics I have nothing else to add, the rest of this post has been uber-helpful. Hope this makes things that much easier. Good luck!!
Travis...aka Petite (Remora)