I have this set up with the Prommy in the top slot; my solution is pretty ugly looking, but I am sure that someone more competent could make it look much more nice and permanent. Despite how it looks it has worked fine ever since I set it up:
A4000T remote-mount disk module 1A4000T remote-mount disk module 2Also I made
this thread in case you find it helpful.
If you try this and make it look better, I would love to see how you did it :-)