Does MM 2019 have the ability to print low resolution draft maps? I would like to reduce the size of the file sent to the printer/plotter via a low resolution request. Does MM 2019 have the capability to modify print quality on the fly?
Do you know then if the plotter can handle lower-resolution files? In other words, have you been able to do this from other programs?
If so, then one option is to use a virtual image printer driver to "print" the MindManager file to a large graphics file, for example a JPG, and then print from that. In most of these you can control both the image size and DPI in the print dialogue.
I use ImagePrinter Pro to create and print higher res images up to A3, but you can go to larger size images at lower resolutions.
I was able to create an image of a map to A1 size (in theory ImagePrinter Pro goes to A0, but in practice for some reason it refuses to create anything bigger than A1). This resulted in a 9MB file at 300DPI.
I have no idea how this would have looked like, or if the file outputted to the printer is smaller than the one sent direct from MM, but it might be worth looking at.