Thanks again guys, The towel idea is interesting...I'll think about it but honestly...unless I'm away for more than a day (not likely upcoming) I'll be out there every day/night cranking the heater back up from never less (hopefully) than 50, up to 60+, all the time. Even with a fairly cold spell a few days ago, I have yet to see it go below 50. Trust me, I WILL be monitoring it always. My main question was really just a better ballpark of how cold could it get before I should really be concerned (assuming I WASN't watching it).
Yioryos: Thanks for the kind words... the 2"x6" were the first thing that crossed my mind and an excellent idea but I immediately decided against it due to the reduced width the room would have... I was convinced that my speakers (and most speakers in general) prefer a reasonably wide room, as much as, if not more than length and I just felt that extra 4+" was something I didn't want to sacrifice. Right choice or wrong...who can say... but I'm pretty pleased so far with the results.
Thanks again everyone.