Wow I was not expecting such great answers, so thanks! Reading all the replies again, it seems that I can get by with the poncho/tarp and bivy as long as I am off the trail by September, which I plan to be. Although it may be more comfortable to use a single wall tent or tarptent, at 28 oz as I saw mentioned, even using the silnylon poncho tarp and TIgoat bivy I plan to buy I would be saving 10 oz, a considerable weight savings. Add a cuben tarp, and it only goes up. After thinking about it, carrying those extra 10+ Oz over so many miles, even if it is just OR/WA, for a "possible" storm (seems unlikely before Sept)is not worth it. Many people mentioned that it is easier to cook in the tarptent, however I dont plan on cooking so that should not be a problem. Please correct me if I am wrong, but seems like I can ride out any storm I may see at the end of the hike with a tarp/bivy and save the weight the rest of the 2,650 miles?
As a side note, if I do change the 12 oz sea to summit poncho tarp I have now for a cuben tarp (+-5oz?) is there rain gear that I can add to the system and still save weight? Wouldnt want to add expense for no weight savings. I was planning on taking the poncho tarp as rain gear paired with a montbell wind jacket and possibly a trash bag for emergencies. You guys have been great, I really love this forum! Happy travels,