Good direction, but still a bit of road ahead... Rated 4 out of 5 stars

I also prefer Classic (slim) mode so much better.

The biggest issue is that displayed stats are valid only for last loaded tab. It should only display stats for currently opened tab.

Right now in Classic Style autohide is only applied to "percent" field and it's not optional.
I would appreciate if it was configurable (for example, replace hide checkboxes with radio "show always"/"when loading"/"never").

Otherwise it's would be great already so don't overdo it;)

This review is for a previous version of the add-on (1.5.3). 

...

When I have more time I'll try to make it work for all open tabs, so the information is correct for every open tab, but this is very hard to implement :(

The "show always"/"when loading"/"never" feature for classic mode will be added in one of the future releases.