You might give a bit of thought to trying a poncho. You can get a silicon/nylon poncho from Campmor for under $100, it will weigh about 9 oz, it will keep all but your forearms and shins dry and is well ventilated. They can be a handful in wind unless you tie it down around your waist but otherwise they work pretty well. I used a poncho on my JMT through-hike last summer and it worked well for me. It rained a lot when I was on the trail so it got a good testing. The only complaint I had was that my forearms were exposed to the rain and often got cold and wet. Next time I'll take along some of those bicyclists slip-on sleeves to keep my arms dry and a pair of waterproof shell mitts to keep my hands dry. A poncho can also serve as an emergency shelter too. A poncho also can serve as a pack cover, if you get one cut for a pack, sparing one the need to take along a pack cover or liner.