Here is my experience:
Compression Test -- Remove all of the spark plugs. Either remove the carbs or have the butterflies 100% open. Put a battery charger on the battery so the starter turns the same RPM throughout the test. Check compression on each cylinder.
Leakdown Test -- Remove the spark plug for the cylinder you are testing. Use a wire, stick, or ideally a dial indicator to find top dead center. Run the leakdown test. I own a cheap leakdown tester. I've heard some people say that you need a very expensive one for this test to work properly. My tester always shows every cylinder in the "green" zone of the gauge.....even with an old motor.....
Hope this helps.