I think the general consensus is that surrounds should be mounted between 1 and 4 feet above the ears, and "slightly" behind the listening area. I don't think a ceiling mount can get the speakers into that "1 to 4 feet above the ears" range.
However, the 8s are said to be "very forgiving" as to placement. And, as the photos show, they can be ceiling mounted very well; particularly if aimed slightly downward toward the listening area as Jason has his. Jason says his sound great.
I think the optimum would be to wall mount the 8s, with the enclosed bracket, right against the wall. If you prefer to aim the 8s, then using a Omnimount wall bracket would enable you to do that and still keep the 8s in that 1 to 4 foot range. If that doesn't work for you, then ceiling mount them. No matter which way you go, I think you'll be satisfied.
Let us know what you decide and how it works out (pics, if possible).
