A1: It takes longer but is the easier and less painful way for your characters. make sure you have your hard hitters in the party (e.g auron, tidus, wakka) instead of attacking the little fly thing floating above the machine just attack the main body of the machine. this takes slightly longer but it stops it using the mega cannon and killing you, now all you have to worry about is having some hi-potions to heal your guys on a occasion. (p.s it helps if their defence is up to)

A2: Use lulu to use lighting on the crane about 3-4 times then use you chareter to use it and distory the machine

A3: try getting tidus and wakka's strength up and try to get a weapon with lightningstrike

A4: Slow the machine and hast wakka and tidus then keep attacking

A5: Make sure you keep heaing Tidus and Wakka when they need it. Otherwise hit it like crazy using Tidus's and Wakka's most powerful Attacks. Eventually you'll beat it. It just takes skill, and lots ad lots of potion, Hi-potions, Mega-potions(I'm over reacting).

A6: It takes a while, but use Tidus to heal when he gets confused and use Wakka to attack. Then swtch it up a bit anf use your mst pwerful attacks. Eventually you'l beat it, but it does take a while and a lot of potions, so make you sure you have a lot, oh and phoenix downs.