But how do I modify the small window that appears?
The contents of device notifier depend on what type of device is detected.
And this can be changed in right-click > Device Notifier Settings >Device Actions or System Settings > Device Actions.
There is a list of all actions and the type of device belonging to the action.
I would also like to stretch out the clock info as the day (thu) now overlaps the "am"
Could you make a screeshot of that part of the window so that it's visible what you mean.
The settings can be changed in Digital Clock Settings and System Settings > Locale > Date & Time.
I have a 24 hour clock and thus no AM/PM.
And I would like to increase the size of the virtual desktop squares .Have each one (of 4) the full depth of the bar.
This is called the Pager.
And you can vary the height of the panel to see what's changing.
And/or move/add the panel to the desktop in order to make any size you want.