Dune grass

[double e]

I'm landscaping a house on the beach and he wants dune grass planted. I know how to plant it, but how far should I space them out? How many are in a bundle?-might vary from place to place, and how much money- just curious.

I was told to use the end of a rake handle and punch holes in the sand, then someone comes behind me and plants them.
If anyone has any better wats to plant, please let me know?