Delta_G:
Not arbitrary values. Arbitrary units. Big difference.
...
So with your accelerometer, measure a known value (gravity) and get a conversion factor from this whatever unit that you are getting and the real units you want.
ah, ok, now I understand.
But as stated, unfortunately the raw accx values differ very much from accy and from accz, if orientated accordingly. So there obviously is no reliable arbitrary unit which fits to all, and they all are rather noisy.
That's why I needed the reliable value(s), which had to be expected for 1g earth gravity acceration in raw values, most possibly by design, or perhaps by multiple experimental readings of other people who own that IMU, too.