The print preview window shows the new size laid out properly but the printer feeds only the size which was used to create the preset resulting in clipping if a larger paper and cell size is invoked in page setup or xs white space if a smaller is invoked. OS X 10.8.5, Stylus pro 7890. REINSTALLED PRINTERS AND DRIVERS, DELETED AND REPLACED LR PREFERENCE FILE, Other aps print ok. I
While the problem is unsolved I have found a workaround. If I use the "Printer" button (lower far right) and print from the printer dialed pop up custom paper sizes chosen in the "page setup" are honored and the layout prints as shown in the LR print preview). On the other hand, If I print using the "Print" button the printer feeds only the paper size chosen when creating the preset.