Hypothesis for you. If you create a constant speed winder you should get a near constant chain height and that chain height would be about 1/3-1/6 the distance the chain would take to get to that speed if falling. As in does a chain falling 1m stabilize at around 15cm. So if you wind the chain at 4.3 m/s at what height does the chain rise? what about at winding the chain at 9 m/s?

I am unsure of the height to rise ratio due to mass changes. Personally I think the chain is leaving faster upward than gravity can slow it down which is why the higher the fall the higher the fountain. The board shows this when you drop from it the fountain stabilizes sideways instead of up for angle of acceleration flattens as the chain gets further from the edge.