FireRed and LeafGreen Static RNG

Tools

Load the game with the lua script.
Go to the "Continue" screen and pause the emulator.
Find your initial seed displayed in the lua script.
Open PokeFinder > Gen 3 Static > Generator tab.
Input the seed into the "Seed" box.
Set your target filters (shiny, IVs, nature, etc.) and click "Generate."
- Method should be "Method 1."
- If no results, adjust filters or reset for a new seed.
Choose a target advance from the results.

Your player should be in front of the right legendary, NPC, or Pokéball.
Make a save state to avoid mistakes.
Advance to the final screen before the Pokémon is generated.
- If there's a cry or dialog, that's usually the final screen.
At your target advance, press A to start the encounter or receive the Pokémon.
Check the IVs of the Pokémon.
In PokeFinder, input the IVs and find the advance you hit.
Calculate the delay: Delay = Target Advance - Advance Hit
Enter the delay in PokeFinder and generate again.
Note the new advance number.