To determine the appropriate duration for the annealing step in your PCR protocol, you would typically look at the temperature and the specific graph you have (which I can't see, but you can refer to).
In general, the annealing time is typically around 30 seconds to 1 minute (60 seconds). However, if you follow the hints given—particularly that the "stages of PCR do not 'count' the time that the thermocycler needs to heat up and cool down"—you may want to choose a shorter duration commonly used in PCR processes.
Given that info and common practice:
- 30 seconds is often a standard choice and is reasonable for many protocols.
Therefore, I would suggest the answer is 30 seconds.