I set it to scale to 2.5" x 4". If you like your arts & crafts time you can print them on a full sheet of adhesive stock and just cut them out. It is a little more time consuming but you don't have to worry about registration with the pre cut labels. Or you can always go to the old standby of milk or a glue stick.
I have no idea which Avery tempate you were using, I just dove in with the same aspect ratio that I use for my own labels.
Bottled- NB Holiday Spiced Ale (yuck), Witchy Hilltop ESB, Hoppy Holidaze IPA, Needs a New Name IPA