Something easy to try is using a quartz hologen worklight underneath truck while it sits overnight.
12-16" away is far enough not to burn wires yet give enough heat so you'll be better off than without.

As others have said it sounds like your clutch hydraulics need to be re-bled. My clutch pedal almost identical in +30 to -30. Not sure where you're at in Alberta, but I understand the issues that come with the cold (this coming from Calgary which has been ~ -30c every night for the past 3 weeks or so, and is considered mild to the rest of the province). Not sure what gear oil I'm running currently, but I know it's cheap (probably crappy tire motomaster stuff). Starting the truck almost requires me to push in the clutch or the starter wont turn over the engine. Even when it first starts and is warming up at 1500 rpm if I release the clutch in neutral the input spinning the cold gear oil loads my engine enough to bring my rpm down to almost 700 rpm. I haven't had any issues with the gear oil. Its definitely more viscous in the cold, but warms up quick enough once you get going.

This^^^