I fundamentally misunderstood the potential of the HDRI editor, but with this concept I took the opportunity to get to know this feature more intimately - it's amazing. Also got a chance to played around with the toon shaderl! Scan data from threedscans.com. Mesh clean-up and decimation in Z-brush.
Love that toon shader approach !!! The back vignette can be removed, or be more gentle.
Thanks man, yeah I went back-and-forth about that radial vignette.