This is great! I like how small they are to fit side by side in a top case like that.
But, I must say for anyone attempting this: please please please reinforce your top rack to support this load.
Any bumps at highway speed will cause this load to oscillate and bounce on the end of a lever that is not well-fastened to the frame. The top rack is only attached by two small M5 bolts to the frame and often enough does not rest fully on the tail, allowing free-play oscillation. Adding a lot of mass in the top case can fatigue the bars quickly (I've had my top rack bolts break at speed with a nice "ping!" sound I could hear through my earplugs).
For what it's worth, the older Elcon 2500 in a top or side case is just slightly lighter than 2 of the new 3.3kW Supercharger units (also by Elcon), and does cause this problem. If you load this mass into a side case asymmetrically, the side rack will start to bend to the side over time, especially if any knocks are taken.
Terry's solution for his top rack Supercharger was to weld tubes from the bottom of the top rack plate all the way to the passenger footpeg mount area. I've done passably well by putting adhesive-backed padding between the rack tab and the tail plastics, but the dirt and forces there are enough that this requires occasional checking.