As far as i remember from our operational GLS use (its been a few years) on the 737NG, it is exactly the same as for an ILS, which means 1 dot equals 1 degree, and for the expanded display one dot equals 0.5 degrees.
The PFD basically did not care what it displayed, the values were calculated by the MMR to give the exact same indications as for an ILS. For the autoflight system it therefore was a normal precision ILS signal and it allowed autoland and automatic rollout. Which was not approved of course, but in a testing effort for the german DLR it was used for that and worked absolutely flawlessly, especially considering that no protected areas were needed. In operational use we used it exactly like an ILS, and it seemed to have better beam stability and integrity (no fluctuation of the LOC/GS whatsoever). The only "downside" was, that it was limited to CAT I use.