The MadVR instructions say to use 24hz to play 23.976. That's the setting I use for 23-24 in the MadVR display modes setting. You can also set up MPC-HC to switch to user-defined refresh rates when it enters full screen. Again, I have that setup to play 23.976 at 24hz. There's a program called AutoFrequency that lets you tweak and automatically change your refresh rate as well. I'm also using Reclock, and, though I'm no expert, it seems to automatically play 23.976 at 24hz.
My TV is only compatible with 23 and 24hz (as listed in the Nvidia control panel - I'm using a 470), so playing anything below 29.x at 24hz is the best (and I believe only) solution I have available.