OK, 1st, doing the surrounds on these is a lot harder than it looks, in my opinion. I do a fair amount of surrounds, I say the larger ones are easier to do, far easier. I am currently doing a set of 901's for a guy that got "frustrated" and made a mess on the first few. If you decide to do this, write me and I will share with you my caveats.
The spatial control I have played with on the reciever, I am regretfully old enough to have used them new, and I am trying to restore a dead one at the moment. Diffuses the sound stage for lack of a better word,making it broader, and if there is anything a Bose does not need, its to have its sound stage broadened or diffused. Bose used to make a statement about how music would sound "larger than life". Thats all fine and good, but I never wanted it quite that large. I kinda think of the Bose as the 1st unintentional surround sound receiver. They are beautiful pieces though.
I think in a HT situation 901's could actually be pretty good, especially for the ambient noises of day to day living that also gets portrayed, their broad spread of sound could actually make a movie quite involving.
I think it might be fun to give it a try in the situation your describing