I just made about 60 dozen spritz in the last 2 weeks. I use commercial parchment sheets, not the roll you can buy from Reynolds. The roll is too slippery. I do have the occasional stubborn cookie that refuses to stick, but for the most part, I've got it down. My dough is soft and a little sticky, be sure not to add too much flour. I use it right off the mixer, no refrigeration. I have the Cookie Master electric one as well as the first Cookie Pro. I think they have changed the Cookie Pro since I got mine. I have the pump to 1 1/2 notches on the Pro and the count on the Master to about 2-3 seconds. Growing up, my mom always made them directly on the cookie sheets. She had 2 going, so she could put new dough on the cooled pan while the other one was in the oven. If the pan is hot, forget it!
One other thing I have found for inconsistent cookies is if there is an air pocket between the dough in the tube. I pack it in as tightly as I can. I know spritz are a pain for most, bu they are so darn good! To me, it's not Christmas without them!