You can indeed use the .FitText method in a post-merge macro, but restrict its application to cells in which text wrapping occurs. For example:
Code:
With ActiveDocument.Tables(t).Cell(r, c).Range
If .Characters.Last.Previous.Information(wdVerticalPositionRelativeToPage) <> _
.Characters.First.Information(wdVerticalPositionRelativeToPage) Then
.FitTextWidth = w
End If
End With
where:
• t is the table #
• r is the row #
• c is the column#
• w is the width in points