Three scripts to adjust G3F Poses on G8F. Apply a G3F pose to G8F, then, with G8F still selected, run one of these scripts and it will adjust G8F's pose to correct for the difference in G3F's zero T pose and G8F's zero A pose, making G8F adopt the same pose G3F would on using that G3F pose.
For normal use, using normal G3F poses on G8F, use 'G3F G8F Pose Adjust - Full', which will adjust both arms and legs. The other two scripts are 'G3F G8F Pose Adjust - Arms', which will only correct the arms, for use after using a G3F upper body or arms only partial pose on G8F; and 'G3F G8F Pose Adjust - Legs', which will only correct the legs, for after using a G3F lower body or legs only partial pose on G8F.
There's only the 3 scripts in the zip file, no FAQs, ReadMes, icons or anything. Unzip and put somewhere in your DAZ Studio My Library (Scripts folder is obvious, but can be anywhere you want). For easy use, use Create Custom Action on the scripts so they'll be in the Scripts menu.