Paper size for jewel case slimline

Hello everybody

I own a multifunction Canon 600 R (Europe) print/scanning device with the label printing software CD/DVD label print 1.30b.

I would like to print the paper label for the top cover of the jewel case slimline.
I’m aware that I can choose 4 different paper sizes.
I tried all of them and I do not seem to get a size that perfectly fits the boundaries of where the label need to be inserted. I would like to be able to determine myself the width or height of the area to be cut out after I printed the label. I’m also aware that the print can be shifted, but this does not help me.
It would like to be able to enlarge the printing area of about 2 mm.
As is is now, the paper label does not sit firmly into the boundaries.
If this is not possible I may have to buy thicker paper to keep the label from sliding.

I tried the other paper sizes but they are to large.

Thanks for your help