Breaking The 2Gb Backup Limit

I have a server running with a 250GB system drive and a 2TB raid array. I'd like to backup the system to an external 4TB USB drive.

I understand there are a number of limitations around using Windows server backup. There are a lot of posts on this, and a lot of confusion.

I am not really concerned about bare metal backup, though it would be nice.

So, the questions are:

• Can I use this 4TB drive to backup to? I can see a few people recently with 3TB drives saying that it works fine. I just need to avoid creating the backup drive through the WHS console.
  
• The 2TB limit on server backup. Is this limit the source data, or the destination? If I backup the entire 2TB raid array, and then make significant data changes, will the incremental backup take me over the limit?
  
• Can I set up the native WHS serverbackup of the 250GB system drive as a bare metal restore, then add additional wbadmin backup jobs for the 2TB raid array? Any guides on how to do this?

Thanks for any help.