It is fall in Peru right now, or almost. Depending on which area of the country, it is going to be mighty warm down there. Even during the "cold" season it can still be very humid with lots of rain. I wouldn't put batting in, maybe an extra layer of thin flannel. But, just a thin cotton top with a light flannel backing would work.
I make quilts with a charity group and we put ours together the exact same way as dreamer. It saves a TON of time, just in omitting the binding!
M