A4 is an international size. It is not anything in inches, it is 297mm x 210mm. A3 is twice A4 which is 420 x 297 mm. As already pointed out, you can print 2 per page and cut them. The chances of finding international sizes in North America is about as likely as other countries being invited to the world series. Grin and move on. Best advise is to crop to the 1.41 aspect ratio, send them the file and get them to print it.