rF2 DX11 recommended settings for AMD Crossfire setup ?

[Dirk Steffen]

Are there any recommended settings we should use with dual AMD GPUs in Crossfire mode?
Any preferred Crossfire setting (Default / AFR friendly / 1x1 / AFR compatible / profile) ?

Any settings that absolutely kill performance or have a big no no sign currently ?

I seem not to find any recommended recent settings (just too much clutter on the web with outdated DX9 settings and too much unknowns with the DX11 beta).

My major issue currently is:

1) get both GPUs properly running
2) when I get them to run both above 90% I suffer from occasional FPS drops (stutters) that make no sense

My computer is heavily GPU bottlenecked (my CPU load barely goes above 20%)

Apple nMP with Dual FirePro D500 GPUs on Win10 64bit and modded AMD drivers from June 2017

Assetto Corsa, R3E, AMS run beautiful and rock solid.