Synthetic sleeping bags

Hi everyone,
Two things. We're hoping to hike the Overland Track in summer. My sister suffers from very bad allergies and a down sleeping bag is really not an option for her. Can anyone suggest a good synthetic sleeping bag? She's looking at the One Planet Sac 3 at the moment, it has a rating of zero degrees and complies to EN13537.
Also, I'm quite keen on taking a Sierra Designs Clip Flashlight CD tent but was told by a camping store it wouldn't be strong enough for the exposed conditions of Tassie. Would you agree with this; if so, can you suggest a few other good tents? I'm not to keen on the Macpac's, they seem excessively heavy.
Any help greatly appreciated!
Two things. We're hoping to hike the Overland Track in summer. My sister suffers from very bad allergies and a down sleeping bag is really not an option for her. Can anyone suggest a good synthetic sleeping bag? She's looking at the One Planet Sac 3 at the moment, it has a rating of zero degrees and complies to EN13537.
Also, I'm quite keen on taking a Sierra Designs Clip Flashlight CD tent but was told by a camping store it wouldn't be strong enough for the exposed conditions of Tassie. Would you agree with this; if so, can you suggest a few other good tents? I'm not to keen on the Macpac's, they seem excessively heavy.
Any help greatly appreciated!