12.5 with DELL RD1000, Backup To Disk Folder vs Removable Backup To Disk Folder

I have 6 500gb tapes, my goal is to have 6 weeks of backup.

each tape will have 1 current (for its week) full backup of my servers, and incremental backups for the rest of the week.

Each week - the tape will be replaced - and the new tape will start off with a full backup, etc.

Which option do i want to use when setting up this for the first time, backup to disk folder or removable backup to disk folders?

What are the differences between the two exactly? What should i know before i make a decision.

my problem with a backup to disk folder is when the tape is replaced - the system might realize its not the same folder and error out.. so i think removable backup to disk is the way to go?