I remember leaving the valley floor on a 112-114 degree August day and heading up to the Kern Plataeu. That night it hit 29 degrees where we set up...I can always slide my TQ off if it is too warm but there is no way to slide an insufficient cover up enough when it gets too cold.

HYOH but hey why not get some lighter and smaller packing insulation? Maybe it was missed but are you backpacking?