Using an IK chain I think is the effect you are going for, not used max to rig in years so this video will probably explain it better than I could! https://www.youtube.com/watch?v=Zhb6N3IWf58
I feel the IK chain showed in the video will work just needs some tweaking. I agree with the less bones will make it more manageable so I reduced the amount. I'm not too sure what you mean by the extra floating joint. Are you talking about a bone sticking out of the forearm and ending where the tube/cable starts? Sorry for…