In theory.....
Setting and using a maximum fragment size is good practice for enabling
faster restores.  However the restores that would utilize fragmentation
would be of the nature of restoring a single file, a directory, a mount
point /etc...

Now a disaster recovery would entail a complete restore. Mount the vaulted
tape and start a full backup image restore. It seems that fragmentation
would not be needed. Also there is not a one-to-one correlation between the
original and the duplicated frags. The number and size of the fragments is
usually different between the original and the duplicate image due to the
BOT/EOT on the media. I am thinking of going to an unlimited frag size on
the vaulted images.

Please reply with pros and cons on duplicated image fragmentation.