Even before adjusting anything for test, another clue would be to watch how much pressure increase there is in the last 10 seconds of running compared to say the first or middle 10 seconds. If the pressure is rising almost as fast at the end, then the pump would have more headroom for running at higher pressure.
If the last 10 seconds of a 60 second run only gains 2 psi, then it is slowing down. Setting the pressure switch higher is probably not going to be a good idea.
For a pure test, there would be no usage once the pump kicks on, but it seems to me that by taking a movie of the gauge during a shower would be informative too. So this would be an alternate indication to maybe try before moving on to the test described above.