Hiya,
I know it's been a while, but if you're still looking, perhaps you could email Richard and ask him to send you a template. He did to me. Here it is, pritt-sticked to the back of a manila folder, cut out, lying on my cooker/stove.
my advice:cut the curvy bits first, then the straight lines. This took about an hour.
When I'm brave enough or have more pictures of the location and the planting arrangement, I'll post where I sprayed it.