Step up spring clarification? AVS2

I know what the plugs are supposed to look like. I can't determine tuning changes other than richer or leaner and there is so much more. Read the plugs to determine which way you need to go but don't change jets yet. If you are rich go one size larger rod and lean go one size smaller rod. Use your vacuum gauge to determine which way to go with the spring. That should get you in the game.