Litolier, Lithonia and even Advance Transformer have quite a bit of On-Line Information in several Catagories - from easy to understand [and useful], to extreme [ultra nerd].
Can't give exact URLs, but from their homepages, you could find a lot of this stuff with minimal "Hit and Miss" attempts, therefore minimal lingering about in Hyperspace
http://www.lightolier.com/ http://www.lithonia.com/ http://www.advancetransformer.com/ Some files need IES translation, while others use .pdf [adobe acrobat] files.
Scott SET