That is all.
The create-projects.gradle script should be placed like so:
~/.gradle/init.d/create-projects.gradle
This will enable the tasks createSingleProject (cSP), createMultiProject (cMP) and addMultiProject (aMP) in all projects.
Using the tasks is easy:
gradle [createSingleProject | cSP]
gradle [createMultiProject | cMP] -DcreateNames=<proj1>,<proj2>
gradle [addMultiProject | aMP] -DprojName=<subproj>