The "junior Captain" thing would be a non-starter. If it doesn't work out for you at AC, you will end up being non current on the 320, and have zero real PIC time on the 330.
Favorite question of the non-current contract pilot - "would you like some fries with your burger, sir?
Right now many Chinese 320 jobs pay better than anything else here. Why subject yourself to more pain for less money? Some companies here require 300 plus hours of line training, for TYPED and CURRENT pilots. God knows what you would go through during a transition here.
If I were just coming to China now I would probably do Spring or Tianjin.