The 2019A version of the Gemini Integration Time Calculators (ITCs) gives estimates of the observing overheads for all instruments and modes (except for GSAOI which will be released later). The overheads include the correct number of acquisitions (one for every 2 hours of science), detector readout, telescope offsetting, and time for re-centering of spectroscopic observations when required. These calculations make several assumptions about the observing strategy, so please review your results carefully.
Output for a GMOS long-slit observation with 16 x 10-minute exposures binned 1×2:
