The macros I use are below. They go in the Normal template's 'ThisDocument' module.
Code:
Private Sub Document_New()
'Ignore any errors
On Error Resume Next
Call Document_Open
End Sub
Private Sub Document_Open()
With ActiveWindow
'Ignore any errors
On Error Resume Next
'Reduce flickering while changing settings
.Visible = False
'Switch to a single view pane
.View.SplitSpecial = wdPaneNone
'Switch to Normal mode
.View.Type = wdNormalView
With .ActivePane.View.Zoom
'Set for a 1-page view
.PageColumns = 1
'Initialize for best fit
.PageFit = wdPageFitBestFit
'Test zoom % and reduce to 120% max
If .Percentage > 120 Then .Percentage = 120
End With
'Switch to Print Preview mode
.View.Type = wdPrintView
With .ActivePane.View.Zoom
'Set for a 1-page view
.PageColumns = 1
'Initialize for best fit
.PageFit = wdPageFitBestFit
'Test zoom % and reduce to 120% max
If .Percentage > 120 Then .Percentage = 120
End With
'Display the Rulers
.ActivePane.DisplayRulers = True
'Hide the mailmerge task pane
CommandBars("Mail Merge Panes").Visible = False
'Restore the window now that we're finished
.Visible = True
End With
End Sub
As you can see from the code, I prefer something larger than 100%, but changing to 100% or 110% shouldn't affect the overall effect.