The other trick to posing props is to add them to Poser figures in the default position and then resaving the prop as a smartprop. If you've already got a figure into a pose you want, just save that file, start a new one, load the figure, pose the prop, parent it to the figure's hand (or whatever body part it's associated with), and save it as a smartprop. Go back to the saved file, add the smartprop, and it should load right into the posed figure's hand.

It would be nice if Poser had a command that would zero an object's origin so that it wouldn't have to be modifed in the Joint Editor. I've tried moving origins in the Joint Editor and sometimes it's a breeze. Other times, moving one axis causes undesirable shifts in another axis and it becomes a time consuming trial and error effort to move it in place. It's often simpler to use the Direct Manipulation Tool (which should have a dials option to constrain motion to one axis).