In case you haven't done it yet and assuming you have the stock 4-position stem, the 8 to 16 deg change is acheived by changing the position of a wedge-shaped washer under the stem. Rotate the thicker end to the front to get 16 deg or the thin edge to the front for only 8. Of course for a larger change you can flip the stem and then rotate the washer as needed. Make sure to check that your bars are level when tightening the stem up, if the washer isn't centered the bars might end up tilted.

I have the same type of stem on my Allez Comp, it seems pretty cool.

Dave