Comparing opiates to Benzos, I think the Benzos take longer.

The opiates have a withdrawal but it is not as long lived. Much of the withdrawal is visceral-- GI tract-diarrhea cramping, sweating, vomiting, trembling, sometimes Blood pressure/cardiac effects. That usually ends in a few days. A craving may remain, but the symptoms will be gone from the withdrawal fairly quickly. The pain may be worse also.

The Benzos can take months in some people. This is because they enhance inhibitory neuron activity. All of our nerves have an action part, and another system of inhibition. In fact the inhibition ones are more numerous! Benzos enhance the inhibitory system, and when removed, the agitation is unmasked and when severe may lead to seizures even. Valium before it was controlled was notorious for this upon withdrawal. So is Klonopin.
I've seen Klonopin users who ran out and were trembling so much they could barely walk!

So I am sure you know this, but I do think you will handle it okay.

This is one MS page with a long supplement list:
http://www.msrc.co.uk/index.cfm/fuse...how/pageid/772

Not all are needed for everyone and it can be dunning reading all that.
The best B12 is 5mg methylcobalamin daily on an empty stomach. This will be absorbed well orally, and help the most.
You could even do 2 a day for a month to get best high levels going. There is no upper safety limit for B12. So it is not considered toxic. Over 90% is not absorbed this way in most people hence the high dose.

Using the methylfolate form of folic acid is also important. I have a member here sending me articles on how synthetic folic acid (this is not bio active in humans) may BLOCK movement of folATE into the nervous system, thru the blood brain barrier.
Here is the LONG article if you want to read it...It is VERY LONG.
http://www.ajcn.org/content/87/3/517.long
So using methylfolate is the best insurance today.