Timings? If you're right at the beginning of the game (which I assume you are seeing as you're going on about your starter) then you can't possibly have the C-Gear yet, which is the only one that would mess up either of the RNGs.Ok, I've finally got my parameters and managed to RNG my ID/SID combination for some good shiny spreads.
Anyway, now I wanted to get my perfect starter but I don't seem to understand how to conciliate the PIDRNG seed with the IV spread seed, since they're supposed to be hit at different timings. I'd be grateful if someone could just explain me how that works.
Plus, the PIDRNG and IV RNG both use the same seed, so I don't know where you're getting that from.
To RNG them, just get it on the right date, then save the appropriate number of times to advance your PIDRNG to the right frame, then choose your starter. Should really be as simple as. Make sure you have your encounter type in the time finder set to Gift Pokemon. If you're going for shiny pokemon, make sure you have "Search for nearby shiny frames" checked, make sure you define what IVs you want and what nature you require as well. Also, I reccommend you set your keypresses to at least two, it will provide you with an easier time of finding good frames within a certain date.