Have you tried changing the order of the last few bookmarks? Like maybe making the last two bookmarks which have their own image and not the generic page image.

The only other thing that I can think of is to specify the max size for both the Location Bar and the Search Bar using userChrome.css, making each of them a few pixels smaller.

I have tried userChrome.css and failed. The only thing I am finding works is removing all the other buttons along the toolbar that I use regularly which is rather disappointing. I can live with the extra bookmark at the end being hidden as I just leave it as a bookmark I never user.

It would have been nice to have forced the sizes but it seems an add-on or something I am using is changing the sizes on start-up, as I see the sizes jump a little as it is loading.

I may just have to live with this...

But thank you very much for your reply :)

You're welcome.

That >> with Bookmarks Toolbar items was a lot worse 5 or 6 years ago, Firefox did that by itself, it wasn't being caused by an add-on in those days. I stopped even using the Bookmarks Toolbar as a result, and even after two related Bugs were fixed I never went back to using the Bookmarks Toolbar for individual bookmarks. One folder of bookmarks in the Bookmarks Toolbar items, which I move to the right of the Search Bar is all I have used for the last 5 or 6 years.

You can try to hide the chevron in the Bookmarks Toolbar items.

#personal-bookmarks #PlacesChevron {display:none !important;}

Try to write these strokes to userChrome.css (with #symbol at the beginning of every stroke)

urlbar {max-width: 850px !important}

urlbar {min-width: 850px !important}

searchbar {max-width: 279px !important}

searchbar {min-width: 279px !important}

Just play some with values. Enjoy :)