I am on the tour at the moment, and as we speak, the 20kg does not seemed to be inforced to heavily, and you probably can get to 23kg, but I would say be prepared to shift it to your hand luggage if things do change, as for hand luggage as long as it fits the dimensions of the restrictions the kg seems to be ignored, we have seen people, locals that is, with boxes of apples, well over the hand luggage weight.
But remember this is what we are experiencing, at the moment.
I will say the laundry service has been excellent at all the hotels so far, we are at chengdu at the moment. Pandas tomorrow.
Hope that may help, but l would say try and travel light, you don't have time to change most evenings, due to traffic, use the hotels 24 hour laundry service, put it in the bag before you leave in the morning its back by 7ish that day. It is a little expensive but cheaper than excess baggage. 3 shirts, 1 pair of trousers at xi'an £14.
Be prepared China is nothing what you imagined and until you get to Xi'an you don't really see the true China, its a great holiday so far. And don't be to worried about the Xian hotel the next at chengdu is as good as Beijing, but so far Beijing has the top breakfast choice, and I mean choice, you will see. By the way Xian hotel is good and clean, just in need of renovation and brightning up.