Gen4 Shiny Patch Mechanics. Anyone know them?

[Gartacus]

To keep this short, basically what I'm wondering is how/when it's determined that the Pokeradar will spawn a shiny patch. I am playing on Platinum.

I want to abuse the save states of emulator as much as possible to help with Pokeradar chaining. Obviously this makes it pretty easy, so getting to a 40 chain is no problem. But after that, what is my best strategy? Can I savestate, use the pokeradar to spawn four moving patches, and then if I don't see a shiny patch, loadstate to go back just a few seconds and somehow get a reroll on the shiny odds for those four patches? Or is it somehow predetermined what the spawns will be, once the radar is changed or something?

Just wondering about the details. I probably won't entirely understand the answer but that's okay...

Thank you!

G