Okay, first results are with unadjusted transmaps, four setups previously mentioned. No pose or material was changed on model or hair between the 4, only light setups. You will notice my renders are not nearly as strongly lit. Also note in all cases the extremely poorly defined flyaway ends.

1. HDRI on background as defined by ghostship in their tutorial on poserfsoftware, used as a light source.

(ignore that crack on figure, forgot to convert to unimesh and subdivide model, fixed in later renders)

2. HDRI on background as provided by bastep's free shader, used as light source. Used exact same HDRI:

3. Sphere and infinite background from Afrodite-Ohki's LevelUp Superfly package available here; no light except the sphere material.

4. EZ Dome, using sun light properly placed based on IBL on dome:

Next post will include some variations based on the transmap of the hair adjusted by the curve shown below and replaced on all hair materials.