Drew: Well, initially, it appears that the diagonal either misses the corner of G2 by about 660" when aligned to the corner of G1 from G3...
SC: You are correct - G2 SE corner sits slightly off the Lehner-Goedicke line although the platform or terrace upon which G2 is built is much closer to the line. There is a very good reason why G2 was 'misplaced' from the Lehner-Goedicke line and it is explained in the Flash presentation here. You might want to click on the pause button on the control panel at the bottom-right of the presentation window.
Why G2 is Offset from the Lehner-Goedicke Line