S3 Bucket for Tape Gateway??

Hello

The tape gateway stores the data in S3, How can I see metrics for the S3 Bucket itself? You never specify which bucket to use when you create the VTL and tapes
In Cloudwatch I can see bytes uploaded, but I would like to know how much data is in the actual bucket, and how many request that has been made.

I need to compare backups using the VTL vs using object storage