I am yet to see any MSR stand up to any decent amount of wind, something to consider if you plan on doing some time on the tops. For lightweight plus stability in wind I would look at some of the tents from Terra Nova or Hilleberg, I have a Terra Nova Solar Competition and when its got all the guide ropes out is a pretty bombproof little unit, only weighs 1kg too, if you are planning on having the dog inside you would probably need to go to something thats a bit bigger though, have had my dog in mine but hes a Staffy so not a big dog, and it was a bit of a squeeze, have also slept with the Mrs in it, but thankfully we know each other reasonably well..
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