Quote - About the renderwindow:

Python windows has just one function to get a render-size. This function delivers no correct values if the renderwindow is docked. You have to set the size under Menu->Render->Render Dimension.

That one works pretty well on the exporter's side; It's just tedious on the Poser side, as we all are used to have preview = render size. I guess it will get easier when the GUI reminds you about the render size.

The problem is with the camera setting. Check my renders further up. I used v.10e, straight (no GUI), and expected to find the same focal length (around 100mm, IIRC); Apparently it differed a little. Now I don't know if it is because 100mm in Poser and 100mm in Lux mean different things (most likely), or if there was an export hiccup. Sorry, exporter files being always overwritten, i don't have them anymore, and I didn't think to check at that moment.