Each *.svf file is a separate 3D View for the given model.

You cannot consolidate *.svf files into a single one, but you can load them all into the Viewer at the same time.

Your payload is wrong: advanced should be at the same level as views and type. Check sample code in this blog post:
https://aps.autodesk.com/blog/new-rvt-svf-model-derivative-parameter-generates-additional-content-including-rooms-and-spaces