@John I have bought Dell U2718Q monitor (4K resolution, diagonal size: 27inch = 68.47cm). It came with pesky bloatware which maximized any dragged window and turned off laptop loudspeakers. Having disabled the pesky bloatware, I tried to configure Rhino for bigger fonts and bigger icons. It turned out to be long struggle. I tried Options>Appearance to change the font and text size of the command prompt. It did not work - Rhino ignored all changes.
Next I tried to make these changes in Options>Advanced. I was successful, but I noticed two bugs: the font size was 10 times too big, and I had to type lengthy font name because there was no list of the fonts.
(By the way, there is still no documentation of the Advanced Options.)
Next I tried to use bigger panel tabs.
Rhino documentation file: http://docs.mcneel.com.s3.amazonaws.com/rhino/6/help/en-us/index.htm#user_interface/panel_options.htm
says that it is easy to change tab size:
Panel appearance options
Horizontal
Tabs appear in a horizontal row across the top of the window.
Vertical
Tabs appear in a vertical row along the right side of the window.
Tab size
Specifies the tab icon size.
Small / Medium / Large
Show panel text
Displays the panel name.
In reality, it is impossible to change the tab size because the tab size and the show panel text exist only in this documentation.
I still have not figured out how to enlarge text in Rhino menus and panels.