Hi again Spoonie,
My CRPS started in my left arm by having surgery after a bad accident. It seemed to spread sort of randomly but once I fell breaking my right wrist the spreading quickened. After that surgery I became full body rather quickly.
In my case my CRPS is complicated by also having cerebral degenerative atrophy.
I fall a lot when I try to do something out of my wheelchair.
So my answer to you is once I suffered a trauma after having CRPS the spread sped up and it became full body within two years of the initial accident.
I hope I explained myself correctly and somehow helps you...