Avamar initial backup

Hi All,

Could you give me an advise how to configure initial backup from remote sites the best way? We are going to install Avamar grid on the main site and include 6 remote sites to the backup. 2 sites will have a local Avamar appliance and 4 sites will be backed up directly to main site. For saving WAN channel we are going to transfer full backup of the remote sites on the main site on HDDs and... what the next? Just make a backup data from this HDDs with Avamar and after that include remote sites into backup with remote agents and configure replication between grid and remote appliance? Am I right, that after that only new data will be transferred via WAN? What is the best practices for this exercise?

Thanks a lot!