Can you render using reinhard tone mapping and than saving file to exr ? I tried that but it seems that it’s adding extra gamma correction even that save game is set to 1.0. Rendering with “affect color only” ticked doesn’t produce such effect.
When Don’t affect colors (adaptation only) option is enabled the color mapping won’t be applied to the final image.
Only the sampling will be affected by the gamma value. It will sample the image having the gamma in mind but it will not applied it.
Yep and then you need to apply the curve in post.
Actually, my way is :
1) Try to find the sweep spot of burning with reinhard and “Don’t affect colors (adaptation only) option” disable without the sRGB in the VrayFB
2) Rendering with the “Don’t affect colors (adaptation only) option” enable and apply the reinhard curve (or close) in post where you can still tweak even more.
That way you have the power of the sampling which is done as close to your final visual render, and you have the power of true LWF for passes, multilight, etc…
Cheers 
And rainhard curve you do with PS curve?
As far as I’m aware reinhard is just a linear curve with an exponential curve for the highlights? As in it’s totally straight up until just before the highlight starts, then it gradually starts to to curve downwards to bring the burnt areas back in?
AFX, PS doesn’t support 32 bit as good IMO.
Stan