Note that the Cycles for Rhino plug-in isn’t yet part of the official Rhino WIP - it is still released separately for brave beta testers. I’ll have a look at the plug-in right after my current Rhino WIP build process completes and release a newer version when it works for me.
I’ll notify this forum again when I do release here https://github.com/mcneel/RhinoCycles/releases
/Nathan