so, about problems with adjusting gens with Hyuna body:
The problem is the tattoo. Removing it removes the white mask from the genitals, reloading the tattoo makes the white mask reappear. GP can't to fix it (unless I'm doing something wrong, but using the manual). On fresh body as well.
I am using Tatoos G3F. I guess I saw the same kit updated to the G3 & G8. I will look for it and try it, and if it fails, I will probably prepare a version of the skin map with the tattoo already applied.
Many thanks for help and hints.