The first thing to try is to look for another label the same size but with a
different number, for example the ink jet equivalent of a laser label.
However, in this case, I couldn't find one. That leaves you with manually
entering the information.
1) In the label wizard, go to the page where you make the label selection
and click the Customize button.
2) In the New Label Size dialog, click the New button.
3) Entire the desired name for the label (i.e. Avery 6878).
4) Set the 3 options in the option groups.
5) Set the number of labels across on a sheet.
6) Set the appropriate dimensions in the picture at the bottom of the
dialog. This information should be on the label box or on a separate sheet
in the box. If not, you'll have to use a ruler and get the measurements
yourself. The problem with getting the measurements yourself is that if
you're off a little, the labels will "creep" when printing. If this happens,
you'll have to open the report in design view and change the settings under
File|Page Setup...