Resource Pools and Planner

I'm curious how other instances are using resource pools with the Planner feature in Workfront. We have 500 users in the tool I inherited, the one group that was using resource planner was using a single resource pool on their projects that has way too many users. Resource planning is expanding across our org so it's getting complicated and the export is turning out to be too long so something needs to change. Looking for ideas on how best to accomplish resource planning and visibility to our leadership team. 

Things I'm curious about:

How do you set up your resource pools and ensure they get added to projects those users could potentially work on? 

How do you limit the amount of users on each resource pool to get accurate exports from resource planner?

Best practices on standardizing this across multiple groups in a single system?

Any suggestions from others on how they are doing this, would be great.

Thanks,

Kellie