I like to have big buttons without labels, only with icons. In order to make it look like that I configure the icon to show labels at bottom but instead of inserting characters I put a series of blanks, so the icons becomes wider. The only downside for this approach is that the icon is placed at the top of the button. It's not a big deal but it would be more aye pleasing if the icons are placed at the middle of the button. Is it possible for you to make a change that if a button have a text that have only blanks, to place the icon at the middle?
This is how it looks in my toolbar:
You can increase the icon spacing under Preferences / Toolbars / Appearance if you want it for all buttons.
You can also use larger icon images (with empty space around them, or just larger images, as you wish).
My buttons have different sizes so making the global change in preferences is not applicable in my case. Even if I put a PNG image with padding instead of an Icon, it is scaled down in the button. It is only possible to make the button wider using the button label. The label is independent of the size of the icon and makes the button itself wider. If I put blanks instead of characters in the label (and the label is set to appear at the bottom of the button) the button becomes wider but the icon is placed at the top of the button as you can see in the above. Can you modify the behavior of DOpus rendering a button that if the label has only blank spaces to place the icon in the middle of the button instead of the top?
Try turning off Preferences / Toolbars / Appearance / Scale Toolbar button images when larger than standard size and then you can use larger images for larger buttons.