回复：New Concept English II - 66 (02/19/2008)

Clear sound utterances, good reading. I might expect little more intonation change, like, rising tone in the reading.
Also, you're to the point - "started to consciously use back mouth sounding to reduce the accent".
My personal feeling: for back mouth sounding, the sound starting point is the key, ie, every sound (uttered or intended to utter) should start from the back mouth - from arount that part of glottis. Even for lips sound such as "b", the lips used as a device to stop/release the air, the actual starting of the "air flow" is from the near the glottis (this might be a little extreme, but i think necessary for us English learners).