We would like to reassess and set a good base line for the user, power and admin roles. Meaning, setting reasonable quotas for
Restrict search time range,
User-level concurrent search jobs limit ,
User-level concurrent real-time search jobs limit,
Role-level concurrent search jobs limit,
Role-level concurrent real-time search jobs limit and
Limit total jobs disk quota.
How should we go about it?
I would keep the default quotas and doing the adjustments according to customer behaviour. For example, if you have a lot of customers running real-time searches and your hardware is getting too much load, you have to limit the real-time searches for those users or get more powerful hardware to process them. I worked on a company where customers are using too much disk to process their reports(triggering several ad-hoc reports at the same time)and it was getting all the free disk space available on the server, so we have to create a new role and adjust the disk user quota to those users to prevent disk space issues.
That is correct. You can also setup it at role level from web interface go to menu settings/user and authentication, select the role you want o change it and select resources tab.