Backing up browser setting certainly makes reinstalling easier.
You need to show your hidden files (click on "view" in Nautilus or PCManFM
and check "show hidden files") to find them.
Then just copy you .mozilla folder into your USB drive and back again into
your new install. It's not a bad idea to back up the folder weekly or
whatever your schedule is for backing up personal files.
I've got a bit more power in the processor on my X60 tablet so you probably
will be happier without Gnome Shell.
I'm glad to see I'm not the only one in this community who is sick of the all
the trolls and thirsting to offer real, constructive help to a real person.