Just to bring some of the information here for those who are impatient :) The experimentation has led to a theory that Firefly is having problems dealing with the small scale of Poser scenes, and that this is causing probems. The proposed (and demonstrated) solution is to scale the poser scene by some large factor (1000% or so) and that seems to solve some artifacting issues. While I am not sure that that is exactly the cause of the problem or the only way to solve it, it damn sure seems to work and is clever :)