Width Rated 5 out of 5 stars
Yes, the default width would be great. I use the Vertical Toolbar add-on (a great place to hide rarely used buttons) so it is easy to overshoot your set width.This review is for a previous version of the add-on (1.0). This user has other reviews of this add-on.
I will upload a new version after 1.0.1 gets reviewed. It will have same options like 1.0.1 but for two width, 13px (now) and 17px (new).
See versionspage for v 1.0.2 with more "width" options