The Cycles settings are for the Cycles engine, used by Raytraced. ProRender is completely separate to that.
You could at least try updating to the newer version here
https://github.com/Radeon-ProRender/Rhino/releases
ProRender is an OpenCL-based renderer, specifically designed for AMD GPUs. It works on other platforms, but won’t be as fast.
I’d stick with Raytraced and _ViewCaptureToFile and _ViewCaptureToClipboard to pull out renderings.
/Nathan
p.s. if you’re up for some unfinished (but working) mechanism see this post for getting production renders out.