I remember well the struggles starting carburated V-8's, filled with heavy mineral oils back in the 70's. Within ten years we had fuel injected fours with synthetic oils that actually turned over.
A trickle charger will use the resistance of the battery to keep it warm, but at the temperatures you are expecting, bringing the battery inside is a better idea.
We also put our tools inside an oven to warm them up before going outside to use them.
They make magnetic mount engine heaters. You can stick them to the bottom of the oil pan, the block, wherever. You can use several and take them off when you no longer need them.
Granted, its not available everywhere, but I use 0W-20 both for the turnover and to get the oil pressure up faster.