Contents of Set A and B are different. Anyway, forget about the home circuit track. You should try the new dnano carpet track in dnano HK. It's a lot bigger and fun to play with.
I'm not sure if it's just decoration difference. But I think they can be setup together. But if you're serious, you should consider the Mini-Z track instead. I've tried this dnano track. As they are made of hard plastic, it's slippery and body paint can be easily scratched out when you hit the track side.