modifying avery diskette label template for internal 1" gutter?

[Bob from Pentax]

Anyone have tips on reformatting an Avery template in Word to add internal 1"
gutter so that the page prints out 2 across lables 3 down to a sheet? All
existing Avery templates I have found are 3 across. I can recenter and add
perimeter margins, but can't figure out how to add a central gutter between
the 2 rows across. Thanks!

 

[Suzanne S. Barnhill]

The gutter is the difference between the label width and the horizontal
pitch.