Don't feel bad, I know the feeeling. Do You have a Bass Pro Shop near by? If yes - You are OK. Buy glass rattles and insert them right after the bend in the hook. Glass ratles look almost like a needle, so it will be easy. Needle point - tip- towards the loose end of the Senko. Sometimes I insert them from the tip of the hook towards the shank of the hook - only when the fish are aggresive. Does not leave to much room for the plastic to go anywhere. Use a wide gap hook, or you will run in to trouble.
If you would like to have more noise; use a brass ratle. Any time you insert ratles in the plastic it muffles the sound, so depending what the fish what you will need to adapt to the situation.
You can also insert led weights in the senko's head. They look like nails. Just insert them from the shank of the hook tawards the tip of the hook. This will make your senko sink faster.
Good luck and don't catch them all.