Once you go through the steps of Finding Your DS Parameters, keep them stored somewhere safe. You can use them again. Thus, you don't have to repeat those steps every time you RNG another Pokemon.
also note that: You MUST use the exact DS system, game file, and its parameters when you are searching for shiny/IV spreads. Changing your DS system, Wi-Fi Settings, or Pokemon version will give you errors. If you have multiple DS systems, they will have different parameters.