Just started on Latios. Personally, while I prefer normal Latias to Latios, I prefer the green colour of shiny Latios to the orange of Latias. Managed to just barely beat Colress beforehand as well, so I have an emergency Master Ball ready.
Question: Am I doing it right? I saved just on the spot before you step forward and fight Latios. The shininess isn't decided beforehand, is it?
Good luck and congratulations to everyone here!