OFS Account Hierarchies best practices

Summary:

Looking for general guidance on best practices about adding in accounts into OFS_Expense Planning or OFS_Balance Sheet Planning. Configuration is set to use out of the box drivers and accounts for Revenue, Expense, BS and CF.

1. Have you successfully used the OFS hierarchies with a combination of OFS accounts, custom created accounts, GL accounts and/or only using OFS accounts?
2. If you avoid the OFS hierarchies - have you been able to use Drivers, Trend based planning, OOB dashboards/reports, etc? Ideally we'd like to use as much OOB content as possible so that content flows from the IS to the BS to the CF.