Wouldn't bother with it, Rob - while you may know the rules for CB use in the UK/EU, what are the rules for Russia and the other CIS countries? You may need a licence or permit, which may cost money and be time-consuming to get - do you want the hassle?
You're likely to attract some attention from border officials and possibly policemen while on your journey because of your foreign plates - you do not want to give them any reason to harass you. If CBs are not in common use in the remoter places (and I would suspect that they may not be) you do not want them accusing you of spying and listening in to military frequencies etc.
Chances are you would be fine with the CB but given the potential hassles it causes, there are no upsides to having it. In emergencies you have a satphone, so it's not even a useful back-up system.
My opinion would be to leave it!
Cheers,