I spent a good bit of time studying all its possibilities and then had a long chat with them about it. After 32yrs it turns out they are planning to remove the tree after enjoying one more years blooms. 
Like any big tree nut & lover of plums, on hearing such news...I offered to remove it for them as long as i can have it to work on. They agreed wholeheartedly tho somewhat mistified as to why anyone would want a tree with so much rot in it.
I have used an 8" pot for size comparison.
With the help of a few good strong mates I plan to move as intact as possible to one of my growing beds, being very careful not to damage the minimal live vein on the right hand trunk. Once it has recovered & growth is underway I will set a layer on the right hand trunk as originally planned and also start on layers from the left hand trunk. I expect to take a few years slowly layering off bits of the left hand trunk then splitting the whole in half and working up the bases as 2 more trees. I couldnt wait to share this baby any longer, 3 days of keeping my mouth shut about this tree was almost too much to bear
Matt
