What is the suggested rate limit for accessing the OSIG generator API?

I am working on a project where I am required to provision several
hundred mobile devices and GearVR units for use outside of the Oculus
store at a multi-national event. We have manually harvested the device
ID from all of our devices, and we'd like to use the API to
automatically generate the necessary OSIG files. I could not find any
Terms of Use for the API specifically, so I'd like to know what is an
acceptable rate limit so I do not hammer the API unnecessarily (again ).