Err, if you want to RNG on a retail cart, FRLG isn't what you should be aiming for. It is statistically impossible to RNG FRLG on retail due to a variety of factors (though it's easy enough to do on emulator if all you care about is shininess and not IVs).
If you're looking to RNG something shiny on retail, you'd be better off using Emerald since the game's seeding process is glitched (It uses a static seed of 0), or a copy of Ruby/Sapphire with a dead internal battery (static seed of 5A0).
If you're dead-set on FRLG, then you can try following your own example, but the frames can act a little erratic due to a variety of factors, and not having exact IVs will make it difficult to find your current seed.