Make a save state at the start of the encounter. :D
By the way if you're going to RNG it you don't need a synchronize pokemon. In Emerald all it does is if Synchronize kicks in it will pull up the first spread it finds that has the matching nature from the frame you're currently at. Makes it harder to pinpoint exactly what frame you're at.
Also, that link I gave you earlier has a guide in it if you go to that groups main page.
By the way if you're going to RNG it you don't need a synchronize pokemon. In Emerald all it does is if Synchronize kicks in it will pull up the first spread it finds that has the matching nature from the frame you're currently at. Makes it harder to pinpoint exactly what frame you're at.
Also, that link I gave you earlier has a guide in it if you go to that groups main page.