In making springerle, rolling the dough thickly enough before imprinting with the cookie mold will make a big difference in the beauty of the print. A couple of people have asked the thickness in millimeters. For most cookie molds I suggest that the dough be rolled to about 0.50 inches which is 12.7 mm. If a cookie mold is very shallow, roll the dough slightly thinner and if it is a very deep mold, roll the dough slightly thicker. You will be applying additional pressure when you press the mold onto the dough and if it is not thick enough, you will not get the impression of the deeper parts of the carving.
Try it! Using a medium depth mold, roll a small amount of dough about 8mm thick and press your mold into the rolled dough, and then roll a small amount of dough about 13mm thick and compare the prints! Or just try it with play dough and see the difference