My experience with the 10cc has been on the Hangar 9 Meridian and a scratch built Kaos type plane;both between 7-8 pounds.
The 10cc's fly them fine and I can perform almost any aerobatic maneuver . If you are looking for 3D ,unlimited vertical, etc.. on a 7-8 pound plane then you might want to consider the 15cc. As already mentioned it really depends on the airframe you are going to fly.
I also run the 15cc on a 90 size Cessna(stick built) and being a heavy plane it pulls it around great.
Tell us what plane you will be flying and how you want to fly it and we can better help you.