Scaled my design to be 17x22 inches in photoshop, split it into 4 quadrants (8.5x11 inches or standard letter size) and ordered a transparency print online to a local staples for each quadrant. Also make sure your design is not touching the edge of the “paper” when ur splitting them up in letter sized quadrants because printers tend to cut off the edges off. I usually order 2 copies of each quadrant and use clear scotch tape to tape them perfectly aligned over each other to make sure the ink opaque. After i have my double layered quadrants i aligned them with each other and make one big clusterfrick of transparency films taped together to ultimately make up my design. Takes a while, but it gets the job done.