I think it will require some experimentation to get spoilers to behave the way you want them to for roll control. One of the German manufacturers made spoilers that consisted of a series of pie shaped elements that rotated up out of the wing in progressive sequence. In effect the spoiler got longer spanwise as it was deployed. I think this would give much more linear roll control than a conventional single blade or trap door type spoiler. Spoilers stall part of the wing and tend to be an all or nothing sort lift distrubition control unless they progress spanwise during deployment. The aspect of spoilers that is more linear is the drag produced. This means that the more the spoiler is deployed, the more proverse yaw. Trying to get the right combination of roll and proverse yaw could be a real problem with single blade or trap door type spoilers.