When first booting to DOS, the display surface is usually in a 720x400 text mode. That's 80x25 characters, 9x16 pixels each.
To reset the text mode to 80 or 40 columns, color or black&white, use:
mode { co80 | co40 | bw80 | bw40 }
e.g.: mode co80
The desktop and any other apps will be sharing 64 KB of resources. You won't be able to run any other apps at the same time.
So don't use wfw in the VM. Use a Linux distro with a wfw skin instead.