I can´t find much info either, aside from one or two Acacia species that are known to perform well as bonsai(A. howitii springs to mind) people are still trying to figure them out. It will either be bomb proof or temporamental.
I have a A. salignia that has handled everything I´ve chucked at it and it´s a real agressive grower yet I have had other acacia species that did not like anything I did to them. That prostrate one you have looks interesting, may be able to use that to give it a natural weeping look. If you do leave root work for a season then just make sure you don´t cut them too early, I normallywait until early summer to do mine.