Single-Area OSPF Link Costs and Interface Priorities
Learning Objectives
• Configure single-area OSPF on a router
• Advertise loopback interfaces into OSPF
• Verify OSPF adjacencies
• Verify OSPF routing information exchange
• Modify OSPF link costs
• Change interface priorities
• Utilize debugging commands for troubleshooting OSPF

This is one of the OSPF series Lab. More will be add. Those Lab are simples I choose 3 of 4 routers maximum, and creating loopback interfaces, the reason is simple, work more efficiently no reason to be concern with latency, you can also falow the ospf relationship while configuring the routers.

Creating look back it's the samething if you were adding more routers my advice to the participants

Enjoy