Increase raytrace bounces from 2 to maybe 4. That will tend to smooth out light distribution. There will be a cost in render time.

Increasing pixel samples will also help, but it occurs all over the scene, not distributed with concentration on light bounces, so you pay a render time cost for less improvement.

Increase both irradiance caching and indirect light quality to maybe 70; that will cause Firefly to give more attention to light cast by a mesh. It will cost render time.

To save some render time, for Firefly, choose a bucket size which is an integer multiple of two, e.g., 8, 16,32,64,128. Avoid partial buckets at the edges of the frame by choosing a document window size (render size) in which both the vertical and horizontal are integer multiples of the bucket size, e.g., 1024x768, with a bucket size of 32.

Superfly has no speed advantage using integer multiples of two; just choose the bucket size and render size such that the bucket size divides evenly into both the vertical and the horizontal. 1200x750, with a bucket size of 30 (or 25, or 50, etc). Superfly will also be happy using the same dimensions as Firefly, such as 1024x768 with a 32 pixel bucket.

Gamma correction would normally be 2.2

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5