Well, I got the idea partially from your challenge. I am allowed to change my equipment, I can't customize it though. I know you had to give up at Seymour Omnis due to the cheap way he opens up the battle, but if I have abilities on my weapons such as SOSNulBlaze or Fire Ward I may be able to get past Seymour, and even if I do get that far I'm not sure I'll be able to beat Jecht.

Anyways, I just finished beating the Chocobo Eater.

Mi'hen Highroad has been more difficult than anything I've done so far in leaps and bounds. Enemies went from dealing 60 damage to nearly 200, and don't forget Bombs with 850HP and Self Destruct. I also met my first Game Over on the Highroad. I managed to get myself into a battle with a Bomb and two Float Eyes (I'm not sure what they are actually called here). I defeated one eye but Lulu was quickly KOd by a Bomb as was Tidus, Wakka didn't last much longer. After restarting I made sure to heal between every battle.

Anyways, I got a few good pieces of equipment on the road from travellers:

Red Ring (Fire Ward, HP+10%)
Hunter's Spear (Piercing, Sensor, Strength+10%)
Ice Brand (Icestrike)

There may have been one or two more, but they weren't helpful enough for me to remember them. I'll check them later.

After making it to Rin's Travel Agency I stocked up on Potions and Pheonix Downs again as well as bought some new weapons and armor:

Pearl Bracer (MagDef+3%)
Something(:P cant remember) Moogle (Mag+3%)

I then proceeded through the cutscenes and rests before the Chocobo Eater.

Chocobo Eater
~ Kimahri, Lulu, Auron

Chocobo Eater was surprisingly easy. When the battle first started it instantly KOd Kimahri with one shot. I revived him with a Pheonix Down from Lulu and then switched Tidus in for Kimahri. From there here is what each character did:

Tidus - Attack ~ Average 30DMG (Delays Chocobo Eater's turns with Slowtouch)

Lulu - Cast Fire (Chocobo Eater is weak against Fire)

Auron - Use Power Break once, then attack over and over ~ Average 200DMG

I switched Wakka into the battle twice to inflict Blind on Chocobo Eater with his Dark Shot (5MP per use, Wakka has 10MP). Yuna pretty much stayed out of the battle except when I periodically switched her in to heal (she averages 500HP per Cure, whereas my Potions only did 200).

Lulu was KOd twice, but that was the only setback throughout the whole battle.

~