For this to work, you will need RES version 4 or above (which comes as an add-on rather than a Greasemonkey script).
- Go to your existing Firefox profile inside the AppData folder. Location of this vary for different versions of Windows. They have been conveniently aggregated over here.
- Find the folder named 'jetpack' inside the profile folder, which has a weird name (scrambled letters and numbers).
- Inside jetpack, find the folder named jid1-xUfzOsOFlzSOXg@jetpack.
- There should be a folder called 'simple-storage'.
- This should have a file named 'store.json', which has all your RES settings. Copy this over to the same location in the new Firefox profile. This location will only be available if you have RES v4 or above installed already.