OK, the test has been run using my old connections and procedure from 7+ years ago!
With hatch open and both outside and inside lights still on the 12v battery current was about 8 amps.
After 10 minutes or so (didn't time it), only the inside cargo area lights were on and current was about 1.5 amps.
After about 30 minutes the inside lights were out and current was about 0.25 amps.
About 20 minutes later it was the same.
In my previous test the current eventually dropped to a much lower value but even 0.25 amps all night shouldn't be a problem unless the 12v battery was about dead to start with.
In any event, you should get one of those little lithium-ion "jump-start" packs so you can "start" the car in the morning (or any other time) in case the 12v battery does ever get run down too much for any reason. There are posts under the hood on the right side for this purpose - quite easy to do. No need to get in the back where the 12v battery is located.