I use a wireless remote switch to control the block heater. Click it on a couple hrs before needed. Right now the block heater is on full time, battery blanket is always on. -35c for a couple weeks.
Ouch, that's cold alright. Got myself a battery tender. The battery is in an awkward position on my Kioti LK30 and would be a pain to boost if needed. Now connecting the tender terminal to the battery will also be a pain but only have to do it once.
The coldest it has been here so far is -22.8C according to my weather station. It's been mild here. I even washed my car outside on January 1st!