Kinect IR Range

Hi all, we are experimenting with projection mapping a dancer (or two) and we plan to use the Kinect. I’ve managed to create a silhouette with the Kinect TOP, and I think we can use this to manage the framing of the projected content, but what I’m really curious about is the reasonable range limits on the Kinect sensor.
Has anyone hit limits with depth? Has anyone ever found benefit in using additional IR emitters? Could they extend the range, or might they actually make it more unstable? Are there possibly any tricks to making the IR image more accurate? For example, are there materials that are more or less reflective of IR that could help isolate players?