You have a lot of specific questions so it is good you started a thread, I am putting this link in here just for reference as you may find some helpful tips in this thread as well:
http://forum.calgarypuck.com/showthr...ht=backpacking
GGG recommend the Exos for me in that thread and he was bang on, highly recommended. Thanks again for that GGG.
You may feel that the people in here are a bit extreme at first, but honestly packing light is going to make a huge difference in the long run, so take their advice.
I also have a lot of MEC stuff including camping gear like a tent, multiple sleeping bags/pads, clothes etc.. their stuff is good, inexpensive, and as others have said they stand behind their products. That being said, most high end companies will.