I have a Big Ox too. I don't have any issues with the SSQA. I drive up to the blade curl my loader under it and pick it up easily, and then hop off and lock the levers. I try to get it centered relatively close, but it doesn't seem to matter if I don't. I think there's about 1/2" of free space on each side on mine. I can see the sides of the plates from my tractor seat, if I lean over a bit to either side. That's probably what makes mine easy to attach compared to Eric's issues. Part of that is due to my loader's curved arms, but it could be easier for me to see since I always detach the blade on top of casters so I can roll it out of the way in the barn. That raises the blade a few inches and might give me a better view.
It does have a lot of vertical float, which is a must for my undulating driveway. I keep the FEL arms raised enough to let the blade float on it's own and that keeps the weight of the FEL on the front wheels for traction and control. It also floats side to side like you said, again a must for me. I keep the shoes set at a point that allows me to raise the FEL slightly which rocks the blade edge down (since it is floating) for a clean scrape, or lower the FEL slightly which rocks the blade edge up above the gravel as is rests on the shoes. I make adjustments as I drive depending on conditions and how much gravel is exposed. Once I get a good hard pack in the winter I can drop the blade and fly without worrying about the gravel.
I've had mine for 10 years. If I was buying a plow today, I would get the same thing.