For the best resolution, the maximum amplitude of the signal you are interested in should be reasonably close to the chosen range without exceeding it. That way, the minimum change in voltage discernible in digitization remains small in relation to the signal being measured. Typically, a range setting of 2 - 3 times the maximum expected value is sufficient. Please note, changing a waveform’s on-screen display (by enlarging it in the Zoom window or by stretching or shrinking its Amplitude axis, for instance) does not affect its resolution, just its appearance.
To learn more about how to choose the appropriate range and sampling speed settings in LabChart, please review the instructional guide located HERE.