Whats the recomended way of storing rman image copies, incremental backups, and archive logs offsite

My backup strategy currently incorporates rolling forward image copies to achieve incrementally updated backups. I'm  using local storage but I'd like to copy the entire rman catalog (all the backup files) offsite..

Every hour I take archive log backups. (This takes a few minutes to local disk)

Every night I take a level 1 rman backup and if there exists a level 1 backup older than 3 days it is rolled into the original level 0 image copies. (This takes 2-5 hours)

I have five data files and so 5 image copies. One of the copies is 4T, one is 1T, and the others are quite small. This means updates to the 4T file would lead to 4TB transfers offsite over a nfs mount or other transfer protocol.