I did some more research and experimentation and have found settings for those users of MadVR tone mapping that almost completely eliminates the red push discussed here. The test pattern looks very good.
Note I am using MadVR beta 166.
And a heads up for those using an NVidia GPU: The "Digital Vibrance" setting in the NVidia control panel, despite being in the desktop settings, rather than in the video settings, will completely change the saturation of the video signal being sent to the display. I'm running it at 45 on my system.
I'm including a screenshot of the config page and one of the saturation test pattern.
