I wanted to thank you for this post. I've been trying to RNG Thundurus all day but I keep hitting the same snag, and I know it is, most likely, wandering NPCs. I'm in dire need of advice.
Right now, I have saved inside the woman's house. With my current seed, I am able to exit the house, get through the dialogue, and end up, fairly consistently, with a roamer on frame 530. After doing one advance in the game via saving (I don't have a chatot...would it be worth it to get one?), I ended up with a roamer on frame 532. Yet another advance yielded 534.
My target was 540. After hitting 538 repeatedly, I was getting excited, only to find out that the next advance, which should have put me at 540, put me somewhere around 600 consistently. I've had this problem with two other seeds....I get really close and then get some ridiculous jump like that. The only thing I can figure is that it has to be wandering NPCs.
Can anyone offer me any advice on the matter? Is it worth it to just keep plugging away and trying multiple seeds in the hopes that one of them won't make that jump?