  The Thousand Pulsar Array (TPA) project currently monitors about 500 pulsars
with the sensitive MeerKAT radio telescope by using subarrays to observe
multiple sources simultaneously. Here we define the adopted observing strategy,
which guarantees that each target is observed long enough to obtain a high
fidelity pulse profile, thereby reaching a sufficient precision of a simple
pulse shape parameter. This precision is estimated from the contribution of the
system noise of the telescope, and the pulse-to-pulse variability of each
pulsar, which we quantify under some simplifying assumptions. We test the
assumptions and choice of model parameters using data from the MeerKAT 64-dish
array, Lovell and Parkes telescopes. We demonstrate that the observing times
derived from our method produce high fidelity pulse profiles that meet the
needs of the TPA in studying pulse shape variability and pulsar timing. Our
method can also be used to compare strategies for observing large numbers of
pulsars with telescopes capable of forming multiple subarray configurations. We
find that using two 32-dish MeerKAT subarrays is the most efficient strategy
for the TPA project. We also find that the ability to observe in different
array configurations will become increasingly important for large observing
programmes using the Square Kilometre Array telescope.
