Though it only works on the Japan/Indonesian/Euro(?) version of FFX, I decided to try this. JAP International version.
Blazed through Dark Ifrit with Protect, Auto Phenoix armors, Celestial Weapons, and Aeons. Then I did the talking to the Al Bhed trick. Which didn't work. So I decided it didn't work.
So, tried it again. And it worked. o__o It allows you to re-enter Home like nothing happened, with Yuna in your party, item boxes previously opened, everything you've collected and such. It's so awesome. O__O Kudos to Gamefaqs. They say some nasty glitches happen, but I have yet to come upon them, and I'm close to fighting Flux.
lol, just giddy about doing this and it worked. Now I can own Yunalesca with super ease.
If anyone has those three(not sure about the Euro version) versions, definately try it. It's so cool. o.o