I camped below Dun Saddle on Saturday night. It's the mineral belt, so not a comfy spot to bed down!
Joe at Zpacks.com did a great job on this tarp. I got the version without netting as I use a bivy bag with my lightweight sleeping bag, great protection against rain splash and extra warmth if weather turns nasty.
If it's mid summer with high temperatures, I put the bag on top of the bivy.
I also use a Gossamer Gear Polycyro ground cloth. Not really needed as my bivy has a sil-nylon base but for a couple of grams it adds some extra protection to the bivy if really damp or rough ground. I use to use a piece of tyvek (would still recommend this and may go back to it, but heavier than polycyro).
The Hemamid is made of cuben fiber - incredibly light and strong and 100% waterproof. If it's good enough for Americans Cup sails it's ok for us backpackers! I got Joe to sew an additional beak on the front to stop rain splash in NZ conditions. He liked the idea so much that he has added it as an optional extra. See photo below.
If you check out You Tube you'll see a clip of the Hexamid in heavy rain. Joe also has a great snow shot in his CDT pictures on his website.