We continue our treatise on beating Final Fantasy X the Easy Way with the end of the Mi'ihen Highroad and the beginning of Operation Mi'ihen.
Talk to the Crusaders around here. Nearly all of them will give you something.
Donate some Gil to Operation Mi'ihen if you like. A hundred Gil nets you a Scout ball for Wakka, 1,000 Gil earn you a Spear for Kimahri and 10,000 Gil earns a Moon Ring for Yuna. The Moon Ring is nice, but its value at 10,000 Gil is questionable.
Spend some time grinding the Mushroom Rock Precipice. There are some nice fiends down here, as well as lots of loot.
Be aware that your dialogue choices with Luzzu and Gatta in the command center will determine which one of them lives and which one dies.
Destroy the arms first when you fight the Sinspawn at the command center. Have Auron use Power Break and Armor Break on them.
Attack the head of the Sinspawn only after you've destroyed the arms.
Have Yuna cast her Nul element spells during the battle. This will help a lot.
Beat Seymour! If you want to see Seymour's Overdrive, the second phase of the Sinspawn battle is your only chance. In order to see it, you may have to smack Seymour yourself (what a crime...) because his Overdrive mode is set to Stoic. Hit him enough and he'll be able to throw his Overdrive.
Leveling Lulu to the point where she has her second-level attack spells (Fira, Thundara, Blizara, Watera) will greatly aid you in the battle with the Sinspawn.