Drawing overrides in Maya


I’m working on a tool to manipulate vertices of a mesh by proximity. I would like to highlight the vertices in question, but preserve Maya’s current vertex selection drawing. I’m looking into various examples in the documentation, but I’m not sure what route to go. I assume I need to pass the mesh/verts. I’m downright in analysis paralysis… the following seem pertinent:

cvColorNode.cpp: custom Locator and use MDrawRegistry to do the drawing. Need to create a custom object however every time I need to draw/highlight verts.
viewOverrideSimple.cpp: can I pass the scene node as a param to perform the draw…?
viewRenderOverride.cpp: oof… overkill? Maybe just use the MUserRenderOperation…

I’ve never done any direct viewport drawing in Maya so any advice or suggestions would be appreciated.