As you can see they're huge and are secured and tailored to each child's head with a brad and rubber band.
For girls I put a piece of tape over the brad's legs so that it would create a seal and not pull on their hair.
I've never used a template for these antlers so I don't have one for you to print. However, with any 18 X 13 construction paper you can easily make one antler set per child. I like to make durable templates out of Manila folders so I can use them to trace and not worry about tearing them.
Or
To further personalize the size to each child's head you can put the brads further back or use a smaller rubber band.
Here's the class sporting their look. In years passed I put a little bit of red lipstick on their noses for a pop of color.