You coullldddddddd and just turn it down. My buddy has a 12g bio and has the hydor mini in there and it actually does the whole tank perfectly with a light-medium movement. Pretty even amount of flow too. Although, he also has that hydor rotating attachment that goes on the return pipe that circles around as flow comes out too...
MJ 606 would probably be fine. I use a 404 on my daughters 6gal and I have to close it almost all the way.
Another idea would be to upgrade the return pump and use one of those hydor rotating thingys. Works well.