Need help modifying label format


I've done this many times before but for some reason this time it just isn't sticking! I have some old, odd sized sheet labels that were designed for file folders but I want to print my return address on them so they're put to better use. But the page itself is 8.5 x 10.5. Now I have tried changing the page then opening the label (5366) but the minute I do, it changes the overall page size back to 8.5 x 11! So, then I tried changing the page size back after opening the label template but it doesn't work. Then I tried choosing Quarto as my custom page thinking if I opened the label template after choosing a custom page size that would work, but nope! It changed the page back to standard size again!!!

Any ideas on how to resolve this would be appreciated. I've tried everything I can think of.

Here are the label sheet dimensions: 8.5 by 10.5 and the labels on it are 3in wide by .66 tall and have 2 rows of 15 labels. There is no space between each label going down, but there is a .5 inch margin between the 2 columns of labels and it has a .5 margin on each side and top and bottom. I tried taking a picture but the labels have a glossy finish so it didn't take.

TIA for any help!


Ii have WPX7 Ver on a Windows 10 Ultimate machine - I have all the latest updates of everything.