You will probably run into issues with L1 charging if you plan to preheat in the winter. You are planning to leave your car outside which will result in even colder temps and longer preheat times. If you don't preheat you are going to use lots of battery just warming up the car. L1 will not be able to provide enough power to warm up the car. Now with a 42km average day you should have lots of juice even on the coldest days so this may not be an issue for you.
As long as the car can be plugged in for most (not usually all) of the day, preheating isn't a problem. You preheat about 10-15 minutes before you leave, preheat while plugged in, and you only lose about 5% of charge. 2 minutes preheating, which is what I used in Upstate NY last Winter, only takes 1-2% net charge away, while bringing the interior up from "frigid" to "cool" or "lukewarm." Battery cooling isn't an issue for me, either: with the car plugged in most of the time in frigid weather, the battery heater only came on twice, all of a frigid Winter, both times after the car sat unplugged for days. The charging itself acts as a battery heater.