For those having issues with HD appearing too small under high resolution screens (when running Windows), an update has been posted which enables command-line flags to set the default font size throughout the application. To use, you need to launch HD from the command line (or create a batch script) with the following:
javaw -jar HD6.jar [font size]
for example, the following would set the default font size throughout the application to 18pt:
javaw -jar HD6.jar 18
Windows does not appear to pass font scaling along to Java, hence the issue under high resolution screens. Moreover, there are known issues within Java in attempting to change the font size once the UI has been rendered. This is the reason that the command line flags are needed rather than a new application preferences setting.