The arms are not floating, they are rather neutral (they are made from carbon fibers and aluminium), but the lens (Inon UWL-H100 and Inon Dome unit) are really negative. Together with strobes it gives around -1 kg or little bit more.
I have the same WAL but didn't get the dome (Yet). I'm pretty happy with the lens though. I'm more into macro at the moment. Going to get a new Macro lens +10.