I use Gimp to save a PDF as a .TIFF Gimp gives you the option of changing picture formats to "save as"
GIMP - The GNU Image Manipulation Program
posterazor will tile it to whatever percentage you want. I scaled the 72" as 33%, 50%, 75%, and 100%. The saved file is a PDF tiled. You have to print,tape,and cut. But it's quicker than going to the print shop and back.
PosteRazor - Make your own poster!
The best part of posterazor is after you import the file on the last page you can go back one page and change the percentage,then print. The rest stay's the same. Like the margin, position, and page layout position. Super simple.
Anyone that wants a tiled plan at any percentage can e-mail me and I'll do it for ya.