I shot a film on the FS700 a couple of years ago; used a Tilta Rig designed for a DSLR, but worked fine with the FS700. We were shooting a mockumentary, so very much that 'indie' handheld look. The needs of the rig will change depending on what lens you mount on it. We had a Fuji Cabrio on the front, which is a nice lens, but made the whole thing a tad front heavy. It wasn't too bad, but anything heavier and it might have become annoying. The camera itself sat on my shoulder, which is where I like it for handheld work (I've seen some DSLR rigs where the camera sits in front of the shoulder, which I don't like, and I can't understand how it could balance well). If you're using the news AXS recorder, that would help to balance it a bit. But then, if you're using still lenses, you might not have too much issue.
The rig we had was relatively simple - handlebars, rods for a follow focus, and an external monitor. I had a Focus Puller so I didn't have to worry about pulling focus myself.
It was pretty light - I wasn't handheld all day every day, but I could've without too much drama. I tend to like a heavier rig though, as a lighter rig is a lot less precise (if you can have precise handheld). That often comes down to the camera though - I quite like my operating when handholding a stripped down Alexa.