VMware Fusion lets you choose the style of network offered to your Guest OSes (NAT, bridged, private), but it doesn't let you pick the actual addresses. So, you're stuck with 192.168.0.0/24 and 172.16.73.0/24.
Unless you drop down to the shell:
cd /Library/Application\ Support/VMware\ Fusion
sudo ./boot.sh --stop # bring down the vmnet interfaces
sudo vi locations # <-- THE MAGIC HAPPENS HERE
sudo ./vmware-config-net.pl # re-generate files in vmnet1/ and vmnet8/
sudo ./boot.sh --start # bring the vmnet interfaces back up
If you'd like to read more, start with /Library/LaunchDaemons/com.vmware.launchd.vmware.plist, which has /Library/Application Support/VMware Fusion/boot.sh run when your system comes up.