  Context: In recent years, stellar intensity interferometry has seen renewed
interest from the astronomical community because it can be efficiently applied
to Cherenkov telescope arrays. Aims: We have investigated the accuracy that can
be achieved in reconstructing stellar sizes by fitting the visibility curve
measured on the ground. The large number of expected available astronomical
targets, the limited number of nights in a year, and the likely presence of
multiple baselines will require careful planning of the observational strategy
to maximise the scientific output. Methods: We studied the trend of the error
on the estimated angular size, considering the uniform disk model, by varying
several parameters related to the observations, such as the total number of
measurements, the integration time, the signal-to-noise ratio, and different
positions along the baseline. Results: We found that measuring the value of the
zero-baseline correlation is essential to obtain the best possible results.
Systems that can measure this value directly or for which it is known in
advance will have better sensitivity. We also found that to minimise the
integration time, it is sufficient to obtain a second measurement at a baseline
half-way between 0 and that corresponding to the first zero of the visibility
function. This function does not have to be measured at multiple positions.
Finally, we obtained some analytical expressions that can be used under
specific conditions to determine the accuracy that can be achieved in
reconstructing the angular size of a star in advance. This is useful to
optimise the observation schedule.
