Hi Chewy,thanks CraigS. could you point me in the right direction for a "good" multimeter? there are so many options. I'm not sure what to look for.
Pretty much any multi-meter has a current draw measurement function, but you have to break into the circuit to make the measurement. For current draws over a few hundred milliamps, you'll use a separate, dedicated socket for the probe (see the picture https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1). Your meter's instructions will show the proper connections.
Some multimeters have a lobster-claw-looking probe that goes around the wire under test, allowing you to measure the current without breaking the circuit. Last time I looked years ago, meters capable of measuring milliamps of DC current get expensive really quickly.
For your parasitic draw test, the less expensive meter is fine. You may need a helper to keep the alligator clips on each end of your battery circuit.