I use two Gyres in alternating mode on my Back Reef, positioned vertically at the back corners. It works really well. While one Gyre is blowing water across the upper tank toward the center front, the other is blowing water across the back of the tank, low and behind the rocks. Every 30 seconds, the flow reverses. Anemones absolutely love it, and it's beautiful to watch.
It's been awhile since I set it up, but I don't recall any kit. You just have to exchange the A & B cages per the instructions, and then rotate them, to achieve the flow you want. You do need the advanced controller (unless they have a new one that I haven't looked at). And each Gyre will produce flow along only 1/2 its length in forward, and the other 1/2 its length in reverse.