Testing Recommendations - Agent Controller, Agents, Virtual Users

We want to simulate 3000 Virtual users in a test and we are wondering what the general recommendations are for doing this.

http://readyapi.smartbear.com/loadui_ng/intro/sysreq indicates:

Recommended System Configuration for up to 5000 Virtual Users We do not recommend simulating over 1000 virtual users from one computer. Instead, use one of the following options:

• Distribute your test to at least 5 computers in your network, so that each computer executes no more than 1000 virtual users.

• Run your test in the cloud on a single r3.2xlarge Amazon EC2 instance. This instance can handle simulating up to 5000 virtual users for most tests.

We are using a cloud agent controller - So, from a performance perspective does this mean:

1 cloud agent controller, 1 agent, 3000 virtual users on the one agent spread across 3 scenarios.

OR

1 cloud agent controller, 120 agents, 25 virtual users on each agent, spread across 3 scenarios.

Thanks!