Netbackup vmware policy best practice

Hi dear all, my vmware backup environment includes a vm backup host and about 20 esx host with about 700 virtual machines. Is it necessary to create one policy for each vm? If I use intelligent policy example for each host, maybe backup for 40 virtual machine will run together. Netbackup recommend 4 concurrent vm backup.
Generally whats the best practice and your suggestion for manage this number of vm and host.
Thanks