My search for the holy grail of UL rain jackets for 3-season backcountry travel has led me to these. So which to choose? From what I understand, the OR Helium II is about 6.3 oz for a medium whereas the ZPacks jacket is 4.5 oz. However, the Zpacks jacket is about twice the cost and half(?) the breathability. From what I gather, the breathability of the Zpacks is only about 8000 g / m3 whereas the OR Helium II is around 24000 g / m3? [Not sure if the numbers/units are correct, but this is what I recall reading online].
Thoughts? If the OR Helium II is truly as breathable as the numbers suggest, do you think I could ditch my windshirt (currently a Mountain Hardwear Ghost Whisperer, around 1.8 oz)