Composition should be readable by the negative most of the time. Some abstraction that the negative provides lets you see the composition separated from the details. For example an s-curve in the composition works flipped just as well as when you saw it.
Originally Posted by Ian Leake
As far as lighting, either get it right when you take the photo, or use quick contact prints to verify; detail isn't important. When using artificial lighting, I use my DSLR to verify lighting. You could use this with your model too. It's not a preference, just another tool. I do have a Fuji instant back on the way, so the polaroid method isn't dead presently. This would reduce the need for multiple sittings. While some might consider it trolling, and it's not directed to you, nothing says crackpot like telling someone to come back for another sitting another time because I'm too proud of analog photography to use a DSLR to check the lighting and practice a pose.