The grid fill is a godsend!  It really takes stuff like this to a new level.  I'm not familiar with Poser, or how it manages smoothing, but this kind of triangles on flat surfaces has created problems for me in some render engines too.  You could add a few support edges in there, or also convert them all to quads by removing every other edge in the pie slices, then just add a support loop through them.  Might be less polys then the grid fill, but I dont know.