Yiazmat - Last Few HP Strategy?

I HATE THIS GUY.

SERIOUSLY.

I've got him down to about 4.5 million HP. There are all kinds of general strategies out there, but what's a really, really good one for the very last part of this fight?

I have Vaan, Fran and Basch at level 80. Vaan has the Zodiac Spear, Fran has the Tournesol and Basch has the Masamune (I tried, oh how I tried to get a Yagyu Darkblade, but those rare bombs WILL NOT DROP THEM).

I have my gambits set up with Phoenix Down as the first priority, then Any: HP < 60% = Curaja as second. After that it's buffing with Shell/Protect/Haste/Bravery, then Attack. Esunaga is in there for that post-Cyclone Sap effect.

I've equipped Bubble Belts on everyone but Fran, who has a Ribbon (on the off chance of Stop, at least one person won't be affected).

I've used Expose on Yiazmat as much as I can, but it keeps missing. Occasionally I'll Berserk Basch to get more hits out of the Masamune, but...it usually ends badly.

Right before Yiazmat hits my party with Reflectga, I'll switch everyone to Mirror Mail for a second so it bounces off, and then back to Maximillians.

Is there ANYTHING I could do to improve on this? I'm dying like CRAZY and I know there has to be a better way. I've tried Reverse/Lure (the Omega strategy, if you will) but Reverse A) doesn't last long and B) misses enough to make it not very worthwhile.

sack the great swaords
equip ninja swords
also id level up a lil bit more

Yeah you're better off getting to lvl 99. I use the tank, healer, damage dealer tactic. Make sure the damage dealer doesn't do anything except attack except in emergencies.

i used the same strat just took it really slow.
I think it took me the same amount of time to get the last 4 or 5 bars of health as it did for the first 45 or 46 bars

Equipping armor with low magic resistance helps to make Reverse hit more, if I remember correctly.