Apparently, with the default toolbar buttons, you cannot remove the text, which severely limits the number of buttons that can be displayed across the toolbar. You only have a choice of large or small icons. I asked IDM about possible workarounds, and they suggested created a custom toolbar. I tried that, and got satisfactory results (the buttons look similar to those on UE for Windows.). Here's what I did:
(1) Create a new toolbar: Preferences, Toolbars/Menus, Customize Toolbar. There's a place here to add and name a new toolbar.
(2) You can recreate your favorite toolbars using the window with the left and right panes (Toolbar Items and Commands, respectively). My toolbar is rather large, so I didn't want to do this manually. Instead, I edited this XML file ~/Library/Application Support/UltraEdit/Uex.tb0 to copy the toolbar buttons from the existing toolbar to the new, custom one.
(3) Finally, the new buttons are too small, but they can be enlarged: View, View/Lists, Toolbars, Large Icons.