So basically I need to use a half or a floating point framebuffer format, lower anti aliasing samples, increase refraction rays, lower refraction and reflection limits and not touch the BSP. Simple enough, Thanks

Sorry for the late response ( :zzz: ) .
Here's a render I left overnight :

2h 18m for this one.
that's weird, since it's a much more dance scene and I've added 4 spotlights (instead of the directional I had) and a HDRI (last HDRI was in a slightly different version).

I'll work on some of the above now...
C&C please
Benny

EDIT: almost forgot, I've got no compositing experience and everything I now about post is what I can do in Photoshop if it counts... LOL