This would not be a good idea.   For two reasons.

First,  you would potentially loose one of the major features of
Autorestart, I.E,  memory dumps to disk.  I don't believe that disk dumps
can span across physical disk drives.  Currently the LDEV1 can only be 4GB,
 the OS uses (roughly) 2-3GB of disk space,  this would mean that after
leaving space for transient, log files, some expansion, you'd only have a
couple of hundred megabytes for the dump file.

Second, after building or modifying the dump file, you need to do a VSCLOSE
and VSOPEN.  This is not something you want to do to the system volume set.
  (Can you say system abort.....)