I mean, when you're talking about weight of a rotating part, the scale weight isn't really going to help you find the highest performing unit, despite the quality. What I'd guess you're after is the lowest rotational inertia sprocket. Two identical scale weight sprockets can have totally different rotational inertia values.
Unless you're literally racing for times, you probably won't notice a difference in performance between any of the 'lightweight' specified sprockets out there. You will definitely notice differences in quality though, especially at 520 size. I remember when people were splitting Superlite sprockets, but I think that was mostly rear ones....
Hope this helps. Sorry I don't have any weights/specs on sprockets tho.