The CS is still a great bright outdoor monitor. I've succeded in flying my FPV very happily off it.
I can now use it for the video preview from my M3P via the RC Pro. HDMI out from the RC Pro and into the CS via a UGREEN HDMI to USB converter. Download the USB Camera Pro SDK and use USB Camera Pro as the viewer. It runs happily at 1920x1080 60fps.
I wish there was no lag but there is a little - as I'm flying from the RC Pro screen it is quite tolerable.