First of all, I'm assuming that when you say that there is lots of rocking and rolling when people turn over in bed, that you are PARKED at the time.
Bigger coaches don't do that so much because they have hydraulic jacks which level and stabilize. I'm guessing that you don't have those.
Second, as mentioned above, you first have to make sure your tires, shocks etc are properly installed. I had a new set of shocks put on once, and the mechanic forgot to tighten one of the nuts, which promptly fell off and made for interesting driving.
Third, this corner weighing is important. You can get it done at rallies sometimes, where they have a scale like a bathroom scale on stearoids. Or go to the local weigh station and get total weight, front axle/rear axle, right side left side, and go from there. It is important to know that you are not OVERloaded, which will make a class C handle like a roller coaster, and it is also important to know that you are EVENLY loaded. Also, if you have half a ton of stuff on the roof, that Class C is gonna sway. All the heavy stuff should be as low as possible, and it can make quite a difference. In our case, it's books for our 4months in the South. We don't store them in the bookshelves anymore, but in boxes in outside lockers. When travelling we carry as little water/sewage etc as possible.
Weighing is also important because from it you can calculate the RIGHT tire pressure, or even determine that the tires are not adequate for the load (dangerous).
So if you do all that and are still concerned, then before you embark on expensive bars you should try to define what the problem is as precisely as possible. With our Class C the problem was "tail wag" or roll oversteer, which can be set off by a passing semi etc. You also see that in tight corners when the RV doesn't steer smoothly, but tends to roll and require steering corrections. The answer for us was to stiffen up the rear axle with some rubber doughnuts made by Timbron, which were cheap and easy to install. What a difference!
But you need good advice, and not just throw bars at the problem and come away disappointed.
And a Class C will never handle like a Class A. You have to go slower and be more careful.
Hope this helps and is not patronizing.