Not so much about size vs procedure. On Hoppers, or any other system with a built in hard drive, you can move from external to Hopper to new drive. I've done this a couple times and currently moved from a 2 TB to 4 TB on the Hopper. My Wally has a 1 TB and I want to upgrade to the 2 TB. But where does one temporarily store as you move from one to another ??? I have a feeling it can't be done.