Can't seem to find any ISO recommendations. What's the use able range at 1/60th

Depends on your shooting condition. ISO is the same as a film stock speed. ISO 100 is lowest speed, and on up, with grain increasing as you go. I shoot most things at 1/60th, set my aperature for desired depth of field effect, and adjust ISO from there. On bright days, outdoor shooting, you will need an ND filter too.

It varies greatly by the light in the scene, display size, settings, and taste.

Examples:

Shooting in tungsten at ISO 400 can have more noise than shooting in daylight at ISO 1600.

ISO 6400 looks fine on Youtube from a mobile phone, but is far too noisy for Blu-ray projected on a 50-foot screen.

Certain settings, such as contrast and noise reduction, can affect the level of noise that is acceptable.

Of course, all of this depends on a level of personal taste in how much noise is usable.

is the noise visible in live view? Or only in post?

is the noise visible in live view? Or only in post?

Noise is more easily visible in post.