Has anyone had any real world experience with JE Design’s Clean Cab positive air supply unit…as in, how effective is it, really? Just spent a month camping and fishing in B.C.'s Thompson/Nicola and Cariboo Regions…all on gravel and dirt Fire Service Roads. Both my utility trailer and truck box sucked in fine dust and sand like a magnet. I’m running a V1 XL camper on a Ford F-150…Build #801.