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The Adjacent Seed Tool is off by two frames (the IVRNG actually starts on frame 3, but Time Finder automatically skips the first 2 and treats 3 as 1). Change the frame and it should match up.
To clarify, you do need your SID if you want to RNG shiny Pokémon, but not for non-shiny ones.
And if you use Pokécheck, make sure the Pokémon you upload was actually caught/bred in your Platinum, and isn't a trade/event/etc.
Championship Points are explained here. Basically, you get more points the higher you place in a tournament, and the players with the highest total points get invites to Worlds (Nationals can be entered by anyone, but winning a regional gets you byes for it). If you don't have enough, you can...
In the main window, you need to click Synchronize (in the top left area) which will change to Cute Charm, then set the correct gender and gender ratio and hit Generate again.
Peaked at 1890, then lost to Jio near the end and finished up at 1878, I think that went pretty well overall. I lost track of my battle record at some point, but I completed 88 matches with <10 disconnections so I'm not too worried about getting DQ'd at least.
Thoughts about my team:
Genesect...