Picture posting is enabled for all :)
In my opinion, by far the best way to grow plums in a restricted space is to festoon the tree from the start. This involves tying strings to the branches and bending them over to form a weeping shape and securing the strings to weights on the ground. It helps you keep the tree to a managable height as you can then get to the branches for pruning. I've posted these pics before. The first shows a reasonable example of a mature Victoria plum in a very restricted space close to a fence. It takes up less than 6 ft diameter and crops well.