I have a Hennessy Explorer Deluxe that I will be using this summer for a few 2 night outings. My concern is keeping warm at night. I have a 40F down bag that I will be using and I don't anticipate sleeping below 50F. Will I require any additional insulation for these temps to be comfortable. I'm a cool sleeper so I don't require nor want to sleep hot. If you think I will require additional insulation, what is the best way to do so.