Peter, I assume that it will work equally well for records of varying thicknesses. Since the groove walls can obscure the view, I recommend using a CD instead of a record to make the adjustment to have an unobstructed view of the stylus tip.
Yes, that is how I have gotten some great photos of my stylus using a USB digital camera, though I used a mirror or piece of glass. Unfortunately, the best SRA matches the original cutting angle of the lacquer, and there was no standard for this angle, so 92 is just an average and not optimal for each LP, regardless of thickness. I have tried 92 degrees as is printed on that SmartStylus and as advocated by Fremer. However, I have found that it varies and LPs of even the same thickness have different ideal SRAs, so I adjust for each LP and then make note of the setting for subsequent listens.
Most people will not go to this effort, and that is fine. This device used to set an SRA of 92 while the stylus is on a CD should work fine and approximate a good SRA for most LPs, but I have found that an average setting is not optimal for every LP and the sonic differences with optimal SRA can be greater than differences heard between phono stages, phono cables, and even cartridges.
I applaud Acoustic Systems for developing these tools. They seem very precise and well made.