Yes that will work OK.
StorageTek don’t recommend more than two drives on a bus for reasons of throughput. When a tape drive starts to stream, it runs at its maximum transfer rate. You want every drive on the bus to be able to do this, which gives maximum backup speed and minimum head to tape wear.
You want to get the specs for your tape drive type, and compare that to the specs for the host adapter. If the combined transfer rate for the drives is more than what the adapter can deliver, then consider adding another adapter to the server.