Wally
I usually sleep outside under the tarp in a bug screen and sometimes with out, I do bring a "MRS Fling" for back up its very lite and good size for a two man.  It is single wall tent, I 've come to the conclusion that rain flies are over rated an add extra wieght.  I also have a Mountain Hardware Hammer Head 3 for colder trips, but that one is a little heavy for general use.

//Windsailor