Width of new tab Rated 4 out of 5 stars

How can I adjust the size of the new tabs ? They are much wider than in Chromea and when you have a lot of tabs , the ''close tab red circle'' dissappear pretty fast with multiple tabs open.... . Any customization options ? How can I do this ?

This review is for a previous version of the add-on (10.2).  This user has other reviews of this add-on.