In the guide at http://docs.openstack.org/grizzly/openstack-compute/install/yum/content/index.html (which is pretty rough), they use 192.168.206.130 as the primary IP for the host on eth0 and 192.168.100.0/24 as the fixed range for our guest VMs, connected to the host via br100.
We use 192.168.0.220 for our host, and 192.168.100.0/24 for guests