Vertical tabs really help. i average around 25, but sometimes i get well over 100. Too many tabs on the top bar and they just become icons with a few characters of text, but with vertical tabs you can actually read them.
I use the "Tree style tabs" extension (which gives you outline-style tabs and sub-tabs) and a couple lines of userChrome.css to hide the top tab bar. Very happy they added native vertical tabs, i may switch to that eventually.
i am using Lynx launcher, which is also pretty GNOME-like