How to use LightBakingOutput, MixedLightingMode

I have noticed the LightBakingOutput struct, and it's mixedLightingMode property and the MixedLightingMode enum. I'm hoping this might be a step towards enabling switching baked lighting modes from script. (And possibly at runtime?)

Is there any way to use this in the current beta? I'm looking into ways to switch lightmapping modes per platform at build time, or possibly at runtime depending on graphics settings. (So the project would have baked subtractive and shadowmask maps included, and be able to switch them on the fly)

Thanks for any info.