I would recommend an oil or engine warmer - there are dipstick elements available, however an engine blanket is probably better, as it warmes the whole engine, not just the oil. Have a timer on it, or just turn it on the night before you want to go flying. Even a small bathroom-type fan heater will make a difference!
As for starting cold - easy to overlook is having the mixture closed during fuel pump prime (no fuel!) I fly an injected 550 C185, and it starts within 3 to 5 blades even when it's below zero ambient, with a 4-5 second prime (that's 4-5 seconds of positive fuel px).