The point-by-point response can be found from attachment.
Models Max Min Mean STD EIGEN-6C4 1.007 -1.696 0.048 0.187 GECO 1.579 -1.703 0.041 0.223 SGG-UGM-1 1.003 -1.671 0.052 0.194 SGG-UGM-2 1.003 -1.704 0.051 0.191 XGM2016 1.016 -1.757 -0.020 0.214 XGM2019 1.705 -1.737 0.081 0.213 Point 6: Your method for combining the satellite-only GFM with EGM2008 (sec.