After installing the pads I left them on all night, and the next morning the pack was at 76F and the drive was GREAT! I had a massive EV grin mixed with an EVil EV laugh as I zipped up the largest hill in my commute.
I did find something interesting this morning. I left my heater plugged in last night, and it got the pack up to 76F in 20 minutes (it was already 63F) and then shutoff for about 4 hours before it got cold enough to reactive. The problem was it didn't turn back on! The voltage regulator I used wasn't the one designed for cold temps, it has a range of 0c-75C, where I need the one that goes from -30C to 125C. I did find a few in my electronic component stash that I will install tomorrow.