Handy dandy "HELP SETCLOCK,all" shows you all you need to know:

SETCLOCK

     Alters the system time or system time zone.

SYNTAX


     SETCLOCK  {DATE= date spec; TIME= time spec [;GRADUAL | ;NOW]}

               {CORRECTION= correction spec [;GRADUAL | ;NOW]}

               {TIMEZONE= time zone spec}
               {;CANCEL}
[etc...]

";GRADUAL" is what you want for the "slow" time change.

Also, from within the text comes an answer to one of the other questions
[can "everything" be done with one command?]

     The user may provide SETCLOCK with a date and time, a time
     correction, or a time zone.  The Date-Time form, the Correction
     form, and the Time Zone form are mutually exclusive; for instance,
     the user may not provide specifications for both a time correction
     and a time zone in a single command.


> -----Original Message-----
> From: Dave Darnell [mailto:[log in to unmask]]
> Whoever replies to this, please include the command and
> option to change the
> system clock "slowly" so that the system doesn't have to be
> idle (I played
> operator once, but can't remember how.)
[...]