Hi guys. There's a slightly easier solution.
You just install the "UnBranded" version of FireFox:
The "UnBranded" version of FireFox is EXACTLY the same as the official stable version.
The only differences are:
- "UnBranded" allows unsigned addons BY DEFAULT (no need to mess with any settings).
- FireFox logo does not appear (but of course, like stable FireFox, you can add whatever theme you want).
You can copy your existing FireFox user PROFILE.
The "UnBranded" version will use it without any adjustments or changes.
Of course, you can also create a new user profile & start from scratch.
Currently, I am using FireFox 49.0.1 (UnBranded version) with IHG 18.104.22.168a.