Please note my previous comment about bigger children over running the smaller ones. In larger groups it is worth while having another adult in the DZ to keep some semblance of order.
I have tried many ways of doing this, The first consideration is the container and how the sweets will come clear of it. My most successful method is a conical bag made of rip-stop with two rings in the open top edge to fit to the dropper. There is a long line from the point of the bag that becomes the static retaining line. I have seen various other devices based around cardboard or plastic boxes but they are not easy to roll up for transport. It is a good idea to make several of these bags and have them ready loaded with sweets to avoid the delay when doing further drops.
The second problem is to slow the decent of the sweets, to make the children run further to collect them and also to avoid the possibility of injury. I am particularly fond of a small parachute cut from thin plastic. To make this cut a 15cm square of plastic, then cut a 2cm strip from each edge but leave it attached by the last 2cm as shown in the picture. . Gather the four corners together and staple them to the sweet wrapper. However this involves quite a lot of preparation if you are doing any number.
Another eye catching method is to us a long narrow streamer of crepe paper. Make sure these are rolled up when in the bag or they can get tangled and foul on the bag and not release or tangle together and come down as a single mass. When doing this as part of a display at an event my favoured method is to make a rotor from a piece of thin card about 2cm wide and 15cm long split down the middle of the top 10cm. Each half then has to be folded down in opposite directions. If these are dropped from sufficient height attached to the long thin chews, or similar, they will spin beautifully and be carried well on the wind.
Yet another that works well is to use a piece of paper or plastic approximately 1/4 sheet of A4 and make a cut from either end as shown here. Next take the 2 ends with the red marks, bring them together and staple on a sweet. The size of paper should be adjusted to suit the size of sweet, for a single one 1/8 A4 is fine.
It is some times a nice change to drop small toys such as plastic dinosaurs, but be sure they are not too heavy for the parachute. Try them when no one else is about.
With the right spectators it is fun, once the children have been for their sweets, to drop some nice chocolates for the mums and then get the dads there. This time the pay load can be flour or water bombs. Don't try eggs as these can damage clothing.
