To increase or decrease the amount of confetti, you simply need to use the 'Wait Frequency' slider. The lower it is, the more confetti there will be.
This is my third confetti project. Feel free to use this in whatever way you want. Just be sure to give credit. *To save the confetti for later use, you can add the sprite to your backpack. You can then change the [On start] block to a [When I receive ... ] message block. You may also have to define wait frequency and kill rate, but you can just take those variables out. ENJOY!