First year into shimpakus; kishu , itoigawa, sargentii. All my trees are in in plastic nursery containers.Would like advice on root system. Wanting to transplant into training pots, yes some are worthy and ready (24+yrs), is best to rake out roots, leave as much as possible or slightly trim. I still want to train,progress them. Question is pot size? Slightly bigger pot which can accommodate most root or trim roots back a certain percentage to the size of root ball, if so what would be a good percentage. I understand that the health of tree is the most important. So let's say tree is in excellent health. Any advice would be greatly appreciated.