Can I 4th gen on DSi XL? I only have an AR DSi and I wanted to use the 100% capture code for the roamers.
AR DSi works on DS Lite/Phat as well :P But, yeah, any DS works for G4 (I'm pretty sure).
And you figure out that bit of info by how exactly? Same way one would use to find their initial seed if RNG the old fashion way?
It's basically like Calibrating, but you only have to do it once. Find a place with pokemon Lv. 50+ (If you're on HGSS, go to Mt. Silver, and get to the place where you're outside of the cave and there's long grass). If you have a pokemon at exactly 49 or 50, use a repel, put that pokemon in the front party, and save in the grass. If you have an AR and an IV/EV check code, insert your AR into your DS. Make sure you have nothing in the GBA Slot.
Open RNG Reporter, and click "Seed Finder". You should get a new window. Pick the game you're on, and enter the year and month that's on your DS.
Turn on your DS, and note the minute you press A on the DS menu to get into the game. Enter the game, run around until you get a pokemon, and catch the pokemon. Enter all the rest of the info in the window, and press find (If you need to use an IV Calculator that will give you a min/max range, pick the tab that says "Find Seed by IV Range instead, but at level 50+ you should get pretty accurate results). The delay listed will be either odd or even :]
I'm not sure if there's an easier way, but I don't think it's that complicated. Also, if you can't get to a place with Lv. 50+ pokemon, just go somewhere with wild pokemon and use the "Find seed by IV Range" tab. Hope this was helpful. If you need Screen shots or anything, ask. :]