Yes that is really great work for LDRI and Poser6, the colors ( light) from LDRI coming always to much to light and washed out and need more work on , the HDRI in Poser7 have more acurate light and is much more simple..
and yes every scene need own individual attention , changing  the diffuse at 127,127,127 make the work faster too and the colors show more natural and briliant out.. including natural shades as in the nature where everything is grey too and our brains in this case poser7 give the image the right color..

Thanks for sharing!! luv it!

ah I am not still done with my step-by-step but look in this situation the ground box should reflect also some way a little bit light too to make it even more real as it looks like ..
you can now hide the props in your poser6 scene, put in a reflection ball take a shot ( render) export to photoshop, crop out, open HDR shop convert mirror ball to angular map and export as low range image for poser6 , plug into the ldr ibl light put back the props and render again and you will see how more realitic it will look like .. :)

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