Enterprise Manager / RMAN

For the management of a small but mission-critical production environment, how are people deploying RMAN (which requires its own database/instance for the catalog) and Enterprise Manager (which requires its own database/instance?)

Is the best/simplest approach just a small(?) machine running an instance dedicated to these two tools?

I'll have half a dozen production databases spread across slightly fewer machines and another 3-4 development/test systems.

The idea of piggy-backing "support" tools on the production systems seems awkward to me.

I'm looking for any sort of guidelines and/or best practices. Thanks in advance.

-- 
John Bossert

In what concerns you much, do not think that you
have companions: know that you are alone in the world.

             -- Henry David Thoreau