Drag and replace both files here:
OpenIV: mods\update\x64\dlcpacks\mpgunrunning\dlc.rpf\x64\models\cdimages\mpgunrunning_female.rpf\mp_f_freemode_01_mp_f_gunrunning_hair_01

GTA5: #66 in 'Hairs' (menyoo)



NOTE: It seems like the original creator of the mod missed some hair strands from from the back of the hair which is why you'll see blank spots, so I advise just using front views for pictures