Chaturbate has a helpful
setup guide for OBS. It includes recommendations for resolution given your upload limitations. Do a couple speed tests to see what your upload ACTUALLY is, because ISPs are dumb and variable. Find where you sit and go from there. I've found that using OBS improves the stability of my broadcast over using the in-browser functionality. Even if Chaturbate goes all wonky and my chat freezes, my stream keeps doing its thing because the broadcast is independent.
Tonight my browser took a big ol dump but once I got it sorted, my viewers said that my fps never dropped below 30. That means you can restart your browser if necessary, but also that you cannot rely on closing your browser to stop your stream. Gotta remember to hit that "stop streaming" button in OBS itself.