Seems obvious, but the physical routers represented by the virtual router should lead to the same networks. They should be redundant router in parallel.
Here, router 2 is the primary because its priority is higher than the default of 100
If S0 fails – since it is being tracked – then the priority drops to 90, making router 1 the primary
R1 should probably track S0 as well
If S0 comes back on R2, it takes over again after the preempt delay of 10 seconds
“standby timers msec <20-1000>” added for the navy, because even 3 seconds can be a long time if you are tracking an incoming MIG.