As I was looking for some equipment for the boys in my scout troop, the thing that I realized is that some tents have built in vents so as to reduce or eliminate condensation in the tent.
I have two types of DIY tarps. One three season that is 11' X 68". The other I have is a winter style (to the ground) with doors. Would there be any benefit to put it on my winter tarp, nearer to, but possibly not at the ridgeline?