Using the print dialog there seems to be no option for non-ISO paper sizes (ie - US commonly used sizes.) While A4 is “close” to a US “Letter” (8.5"x11") paper size, it’s not really the same. Might it be possible to build in some US standard sizes?
The best and recommended way to print is to export to PDF or PNG and print the result using your favorite printing tools.
I saw that on an earlier reply on resizing a chart to fit paper - and while that will get the job done, it would be more efficient and simpler if the program used the standard Windows printer dialog that allows for printing to a large variety of formats, ASME and ISO.