Some General Things to Consider:
Number of guests
How to calculate ...
What do we mean by a handful? We refer to a handful as the same as the amount of petals you would get in a standard-sized cone-full of confetti.
Standard-sized cones hold around 100ml volume - so our guidance is based on providing 100ml of petals per portion.
1 litre of petals will normally fill around 10 standard-sized confetti cones (or provide 10 handfuls) ... depending on how generous you want to be. For hydrangea (due to the larger size with the clusters), you may want to allow a little more per portion - so, you can work on 8-10 handfuls / cone-fulls per litre.
Here's an Example Calculation:
Size of your confetti cones / bags
FYI ...If you already have your cones, you can test the volume by filling with a dried food (such as rice or cereal) & tipping into a measuring container to read the volume. This test will also work for envelopes/bags too.
Please be aware if you are purchasing flat-packed manufactured cones for DIY assembly, these are often quite large - so will require more petals to fill (this can be as much as 50-100% more volume to fill).
It's definitely worth testing the volume to work out how much your cones / envelopes / basket etc will hold - otherwise, you are just guessing how much confetti you are intending to provide as portions. If your cones or bags hold more or less than 100ml, then you will need to alter the calculation. We can help you with this if you need guidance.