I had a similar question before my Rescue class, not about doubles but about doing it in a backplate and wing. I decided to go ahead with it, because it didn't make sense to take the class in gear I didn't dive, and I was hoping to get some education about managing my gear in Rescue scenarios. What I got, instead, was two very puzzled instructors, and Bob (NW Grateful Diver) got a frustrated phone call from me each night asking him questions like, "How DO you get somebody out of a harness if you don't cut it?" (Don't ask me why I didn't take Rescue from Bob, who is local -- the answer is long, Byzantine, and husband-related).
So what I would say is not to take Rescue from an instructor who is unfamiliar with your gear. It won't teach you as much as you should learn in the class, and it will frustrate the dickens out of your classmates, because the instructor won't be able to help them with the problems, either.
So what I would say is not to take Rescue from an instructor who is unfamiliar with your gear. It won't teach you as much as you should learn in the class, and it will frustrate the dickens out of your classmates, because the instructor won't be able to help them with the problems, either.