I don't print large decals that often but when I do it seems there are always problems. The material seems to get wavy the further down roll. So this cause inconsistent colors and head strikes on the material. I use media clamps and roll out excess before starting the print. Attached shows the problems I am having. This is the second time I printed this. Seems to start happening about the 4-5 foot mark every time. Don't feel like wasting another 8 feet of material. How do I avoid this?