We are using qpdfview, but the PDF viewer doesn’t matter - printing properties in okular and qpdfview are identical on this manjaro install - A5 and others aren’t there.
SystemSettings->Printers Do you have a printer installed? If not install one. If yes, choose your printer then click the configure button. You should get a new window that says EPSON/HP whatever series printer: Configure Printer. 2nd item down in left pane is printer options, media size is the top option; choose media sizes, apply,
I see. In the case of Okular and qpdfview it doesn’t matter, because they use the same print dialog. Please have a look, they are identical, with the same settings:
SystemSettings->Printers Do you have a printer installed? If not install one. If yes, choose your printer then click the configure button. You should get a new window that says EPSON/HP whatever series printer: Configure Printer. 2nd item down in left pane is printer options, media size is the top option; choose media sizes, apply,
This turned out to be the issue! print-manager wasn’t installed. We had system-config-printer (CUPS) which had limited options (simplified driver?).
Installing print-manager which causes System Settings -> Printer to appear, and then installing the printer through that interface allowed us to choose a different driver, which had all the paper formats.
Thanks a bunch @sweasyf - you helped us home in on the issue!