I have read that refresh rates below 60Hz are bad for your eyes. So my question is should I set my monitor refresh rate to something above 60 or choose optimal?
it depends on what your monitor can support. try setting the refresh@ 85hz at the resolution and color depth you want. if it works that's great. if not the lowest i would try is 75hz then i would adjust my resolution. any refresh under 75hz you're going to see flicker and even some monitors at 75hz you can see it.