4.5 Can a user volume set be changed, adding it to the system volume set? And then restore the files from the user volume set to the new system volumes?

Sure.

1. Store all of the files on the User Volume Set

:STORE @.@.@;;ONVS=USERSET

2. Dismount the user volume set

:DISMOUNT USERSET

3. Use VOLUTIL to SCRATCH each of the discs

volutil: SCRATCHVOL n

4. Use VOLUTIL to NEWVOL each of the discs

volutil: NEWVOL MPEXL_SYSTEM_VOLUME_SET:MEMBERn …

5. Alter all of the groups that were on the USERSET to HOMEVS= (or PURGE all of the groups/accounts)

6. Restore the files to the system volume set

(:RESTORE ;@.@.@;VOLSET=MPEXL_SYSTEM_VOLUME_SET;CREATE)

Step 5 is the most work.