Copy the table that has the size and widths you want to use. Paste it into
the second document above or below the second document's table, with at
least one paragraph mark between the two.
Add or remove rows as needed so the pasted table has the same number of rows
as the original.
Select the original table. Copy. Select the pasted table. Paste. This will
insert the contents of the original table into the cells of the pasted
table, retaining the size and widths, etc. Now delete the original.
