How did you pull that off fellow 8giger?
new UVs so I could combine normals, roughness and diffuse for the body in a single 4096x4096. Face remains standard as here the detail is still the most important.
Share textures among the models (roughness and normal for body) while diffuse and textures for the face all remain unique.
The models are all subdiv 3 doing render but I guess you could also cut it down here when needed. However IRAY works best with somewhat bloated high resolution models.
Strandbased hair was the big challenge because of the insane vertex count (millions of vertex) per hair. So here I had to tune each hair to look decent while cutting the vertex count to between 1.5-2 million vertex. The line tessellation is however set to 2 as pushing it lover will disable the gloss channel (and make the hair simple look bad). For body hair its fine to push it lower.
The fibermesh brows have also been optimized outside of daz though. Used a merchant resource as base for the brows but they were extremely high poly count so I had to reduce that.
If you removed all the hair and kept the UV / texture setup you could have quite a few more characters in 8 gigs. Also doing render do not use caustic or guided render as they take up another 1-1.5 gigs of vram to simply run. So if you need caustic you need to keep that in mind.