Seed replication using NDMP VBB backup?

I'm trying to seed a file system replication by using the Tape Transport method documented in the Replicator v2 guide for 5.6. Using Networker to perform an NDMP backup on a 1.2 TB file system. Currently the backup is only getting about 17MB/sec and is taking 20hrs to complete. I believe the slow backup is due to 99% of the data is small files under 1MB. I'm looking into ways of speeding this up if possible.

1. I'm wondering if I can do an NDMP backup of the file system using VBB (volumes)?

2. The guide states "At most 4 NDMP backups can be active at any time." How would I accomplish this on a single file system?

Thanks,
Aaron