I'll be visiting China soon and will be there for 7 weeks. To minimize multiple foreign exchange conversion, I'd like to know :

1) if Bank of China (Shanghai, Chengdu, Lhasa branches ) accepts traveller cheques denominated in Canadian currency ? And if yes, is there any commission charges involved ?
2) is it also true that the rate offers for traveller cheques is better than cash ? is this only with US dollars, or is it also applicable to Canadian dollars ?

Thanks for your reply..