Installing TRITON Infrastructure - service account

I am re-installing our Websense, after our config.xml got corrupted.  I'm on a screen during TRITON Infrastructure Setup that is asking for:

"Specify user credentials to be used by TRITON Infrastructure and other TRITON Unified Security Center components when running services or logging on to other machines."

What level of rights do I absolutely need to assign to this accout?  We don't like giving Domain Admin unless there's no other way.

Thanks,

Joe