As part of a Delta Skymiles award, I'll be taking flights between pvg-can-cgk and back in September/October on China Southern in business class. We'll be in Asia for over 2 weeks, so you can imagine we'll have quite a bit of baggage with us. I am very concerned over the 20kg weight limit for checked bags that this forum has convinced me is enforced. How much will China Southern charge me for additional bags/weight? Is there also a size allowance on China Southern, or is it weight only? Does business class make any difference?