I really do not know about root pruning and there must be many members who have experience about this.
I always try to get roots as far in as possible because it is there moisture and nutrients are. That goes against pruning them. I try to untangle them if in a pot and stretch them as far as possible.
I sometimes prune the green parts (if not deciduous) in order to avoid that the green parts dissipate water faster than the roots can supply.
Good Luck
Göte
