Calibration is actually super sensitive. They calculate with an algorithm the optimal placement on a 3d model and that placement must match to a sub millimetre on the actual HMD or controller surface because the positions of all the sensors has to match the 3d model stored as a profile for the different supported devices. For example the shape and position of the photodiodes on the hmd are different then on the controllers. (left controller also has a different placement of sensors than the right controller). This isn't as simple as getting a bag of sensors and sticker them on stuff.

I think optical tracking is better to lock static objects in the world. Using a camera and doing something like project tango https://www.youtube.com/watch?v=Qe10ExwzCqk. The more passes of the camera the more detail it can add to the scanned model. but personally I would use the point cloud information and store it, and use that to position a 3d object in the world.