Why would you be trying to work in such high color settings in AE, when your footage is (correct me if I’m wrong) no greater than 8-bit? Does the 7D shoot in something greater than that?
32-bit color space is even more extreme than what I would normally use when rendering broadcast-ready HD 3D animations. The files are huge, and they slow AE down.
If you were going to be introducing substantial effects over your footage, then perhaps I could see the need for the additional color space headroom. But, again, what is the bit depth that you’re getting out of the 7D?