Are you planning on RNGing your Raikou and Jirachi on HGSS or DPPt? I'm sure you have a Raikou on your HGSS game, so I know that I can help you through that. If the Jirachi is on your DPPt game, it'll be a little harder to get.
In HGSS, there is a Pokemart (in Cerulean City) that doesn't have walking NPCs in it. So, RNGing Wondercards in HGSS is much easier. Plus, Raikou's nature is set, so it is probably the easiest thing to RNG in any game.
But, in DPPt, every Pokemart has at least one walking NPC. So, it makes the process MUCH harder. I actually have no idea how people have the patience to RNG Wondercards that do not have set natures in DPPt. You have to enter the game, advance the frame however many times are required and then exit out of the journal and talk to the delivery man before an NPC moves. Then you can verify if you hit your delay or not. Whereas in HGSS, you can verify your delay before having to advance the frame and there are no NPCs to worry about.