I find that on trans-pacifics headed east bound, it's best to follow the first response in this thread. Try to reset your body clock to the destination as you fly. Try to sleep ASAP out of NRT and force yourself to be awake early morning time LAX on the HKG to LAX flight otherwise you may find sleep difficult the first night in the US.

This is what we do with us and the kids, but sometimes we are still up until 2am trying to sleep.