Here is some imperfect data for whoever may benefit from it.
I spent the night at Judy's last night, charged to 80% on L1, but it didn't quite make it all the way.
I started preheating while the My2012 was still charging, outside temperature was -13F around 8:40AM. CarWings was showing 9 bars and 65 miles on the GOM. At 9:45, I took off toward my house, 4 below, 21 miles away, with the GOM at 63 miles, still 9 bars, and 2 battery bars. When I got into the car, the chill was gone, it was far from "heat soaked', but I was charging and heating while on L1, trying to both on 120V equates to neither working very well. LOL
I drove in D, (not ECO) for maximum heat output, 75 degrees on the CC (auto), seat heater on high and steering wheel heater was on. I dropped the 9th battery bar pretty quick, but from there on, I was getting around 3.5 miles per bar.
From the energy screens that I reset before I left:
20.9 miles, 35:16 minutes
36.2 Average MPH
2.8 M/kWh
4.5+ on the CC energy screen the entire trip.
I gained a battery temperature bar during the journey somewhere and another when I was pulling into the garage. So started with 2, ended with 4. It was 3F when I got home.
Ended with 3 traction battery bars and 16 miles on the GOM.
I have pictures of all of this, I will attach them when I have some more time to re-figure out how to do that.
Hope that helps, if even a little.