This has been a most informative thread. I totally agree about the decreasing pearl sizes (actual vs. stated) as well as the shrinking strand lengths, as I have witnessed this firsthand as well. But I have found that the more knowledgeable you are while talking to your suppliers, the more likely you are to be able to get the right size strand length and the right pearl sizes. Just adding my two cents worth......
Below is a link to a video that my husband took when I was on my last trip to Zhuji and was talking about pearl size ( sorry, the video is in Chinese - but I am definitely talking about pearl size and asking that I get the size as stated, and not smaller......). I was not going to put this on, but seeing all this hot debate about the same issue, had second thoughts and put it on just because it seemed so relevant to the topic.
Thanks for letting me share!
http://www.harmonypearls.com/page/negotiating-in-china