By default, each tab header in Firefox has the same width. However, for certain tabs I'd like to have a custom width which doesn't change, or have it's own min/max width settings. To be clear, I want to modify the width of the tab in the tabs toolbar. Not the size of the browser window when that tab is active.
For example, I'd like the tab for my email to be just large enough to fit the icon and number of unread messages. I always keep this tab in the same position in by browser, so having it long enough to fit the name is just wasted space. However, if I'm crawling through the documentation pages for an application I'd like the tabs to be the 'normal' length, so I know what each tab contains (since I normally open a lot of tabs when reading documentation).
Assuming such a thing is even possible, how can I achieve this?