Poser will allow you two bulge maps. One on the actors RIGHT side, one on the actors LEFT side. (Or FRONT and BACK, depending on the orientation of the actor)

pos and neg are the settings for how much you want that map to bulge in (neg) or bulge out (pos) when the actor moves out of its default position.

*

http://www.posersoftware.com/documentation/12/Poser_Reference_Manual/Tools/Joints/Painting_Bulge_Maps.htm

*

I think  Dr Geep's brilliant tutorials aren't online anymore anywhere, but as he used to share them freely, I think it doesn't hurt to post this little excerpt here:

*

About the smooth brush: I use it ALL the time for both weightmapping as well as JCM's.

Best thing since the invention of sliced bread. It's finicky, though, especially if the mesh has "crumpled in".

It'll also happily destroy an elaborately hand painted map if you overdo it.

But as I mentioned, I already see a divergence in rigging "styles". 

I seem to treat rigging  more like clay sculpting, and the more "clay" there is I can manipulate (= high res mesh), the finer I can sculpt.

You seem to have a more "mechanical" view, trying to fully control every single vertice and move it through the 3D space to the exact location you want. So a low res mesh naturally gives you better control.

(The morphbrush actually can do that if you set it to "hard" and scale it's influence zone down a lot, but this "move only one vertex around" setting isn't very precise nor controllable.)

Just be aware that Poser's built in subdivision can change the look of a joint drastically. What has looked great in preview, might not look good at all once subdivision is applied.

But I've seen both ways work, so stick with what you can work with best.

Anyway, it's great to see Antonia getting a remake. :-)