Advice for tapering off of Xanax


I am new and hope someone can offer advice regarding tapering down and, eventually, discontinuing the use of benzos altogether. First, some background.
I was diagnosed with an anxiety, panic disorder (throw in PTSD in that also) in 2000. I was prescribed 4mg of Clonazepam along with Zoloft. I took the Clonazepam until 2005 when I relocated and my new doctor prescribed 5mg's of Xanax per day and I have been taking 5-6 each day since 2005.
Now, without any comments regarding the "why," I self-medicated up to the point of 14mg per day. By the beginning of 2010, this high of a dose was merely keeping withdrawals in check and I still had plenty of anxiety. Consequently, I have begun a very slow tapering schedule, transitioned to Clonazepam again (longer acting) and will switch to Valium at the appropriate time.
I am now, finally, receiving very good therapy and I have successfully tapered from 14mg per day to 11 per day and will go down to 10.5 this week. I'm tapering at 0.5mg per week with minimal withdrawal symptoms.
So, as of now I am taking 8mg of Clonazepam per day and 3 mg of Xanax per day (cutting the Xanax to 2.5 mg per day at the beginning of next week).
My question is: When should I begin the transition to Valium? My spouse is now giving me my medication and I am dedicated to getting to 0mg's!
I know the dose is high still and I was quite hesitant to post this. Yet, going down even 3mg's is a great start and I feel extremely confident that, in a year or so, I will be free of this dependence.
So, I only want to know if anyone else has tapered from such a high dose and switched to Valium and, if so, could the switch to Valium be made now or should I wait several more weeks?

Thank you.

P.S. If anyone has a "dosing schedule" for this amount (don't simply refer to the Ashton manual, then it would be appreciated.

Socrates, I do have a dosing schedule somewhere (I have to find it) that I came up with after reading the Ashton Manual. It is based on the manual, but it is the result of much trial and error on my part. The drugs I was taking were also Clonazepam & Xanax (but at slightly lower doses than you). My taper took about four months and it seemed to take forever to get onto straight diazepam, but it worked--no withdrawal. My sleep pattern, after a year, is still far from normal but improving slowly. I shall find the schedule and post it for you asap.