Create Custom Page Sizes
Paste the text on a new line. Rename it and change the sizes.
Add a carriage return to the line you copied and press Ctrl/Command+V to paste the text.
Give the line a new name, such as Letter Landscape. Change the size values, such as from the default sizes of 8.5 and 11 to 11 and 8.5 for a landscape orientation.
Rename the original file in the Settings folder to keep a copy of it and drag it to your desktop. Drag your edited text file to the Settings folder and launch the Photo Editor.