To complement the growing literature on magnetic prospection in historical archaeology, the practical aspects of magnetometer selection and survey design need to be explored. Based on a test case from the Petaluma Adobe State Historic Park in northern California, two readily-available magnetometers are compared with respect to instrument type (alkali-vapor versus proton precession), sensor configuration and number (total field versus vertical gradient), sensor height, intensity of data collection, and basestation correction procedures. These variables are then considered in light of survey speed, labor input, and monetary cost. Results indicate that the alkali-vapor gradiometer is better suited for historical archaeological research based on survey speed and efficiency, volume of data collected, temporal and spatial intensity of station readings, and sensor sensitivity. In addition, the data reconfirm the importance of sensor height, gradiometer configuration, and basestation correction in obtaining high-quality magnetic data.