You just have to put it in test strip mode and then you can enter any size you like:
- Add your print at the actual size you want to print (let's say 24x36). This tells QU what size the full print will be.
- Click "Edit Page" to go into the full page editor and click on the "Cropping" tab top right
- Click the test strip button (vice icon): this puts it into test strip mode
- Now right click on the print on the full page editor and select "New Size", "Custom", "Specific Size" and enter the size of your test strip (let's say 24x3)
- You can drag the location around in the small cropping window or click the "High Precision Crop" button on the cropping tab to drag the box around there, specifying what portion of the image to print
Note that once you've established your test strip, you can then adjust your page size via the printer driver to make a smaller paper size or reduce the length so you don't have to print a long page on the roll.
So the key is to add the print at the full size so QU knows what size to work with, then click that test strip button. After that, you can set the size to any (reduced) size you like. You could choose 2x3 if you like and it'll just be a 2x3 portion of the full image and you can use the high precision crop tool on the cropping tab in the page editor to move that crop around and get any 2x3 chunk you want from any portion of the image.
Regards,
Mike