Looks like Optiminer uses Global Worksize of 524288, 4 , 1 and a Workgroup Size of 256,1, 1 for each round.
And uses Global Worksize of 640000, 4, 1 and Workgroup Size of 64, 1, 1 for Sol detection.
I just dont know the exact specifics of how that can be used for better effeciency. I looked at the IL/ISA code and its very hard to read pure IL properly.
Each round has around 30% occupancy with the limiting factor being LDS (on my Hawaii Card).
Im not sure where im going with this post im just hoping someone with more knowledge than me can use it ...
Silentarmy seems to have the limitation of VGPR (Vector GPR per work item).