I would suggest keep using the test cut on the machine itself till you get it cutting good. Then move on to your actual design. This accomplishes three things, it give you a known good cut design, it eliminated software on the computer, and it minimizes vinyl usage.
Unless they've changed the patter, the test cut should be a square, about 1" in size, with a star inside of it. You should be able to easily weed the star without pulling up the edges, or vice versa, weed the edges without pulling up the star. After you pull up the star or the edges, pull up the other so that you can clearly see any marking on the backing paper. At most it should look like you ran a pen over it and put a slight indention into it. If the backing is cut at all you have too much blade exposed.