Did I read you are taking a 5 day shakedown hike? Is that your only hike planned before the thru? I've only just started last fall, but have done 4 hikes so far with at least 2 more planned this fall. I find I am still figuring out what I like, don't like, use/don't use. Was not sure if this 5 day trip is your only experience, if so perhaps do some additional trips trying things out.
As for saving weight, my pack started a little over 40, and I've already replaced my tent saving 2.5#, replaced a camping pad with a lighter neoair xlite saving a pound, Before doing a thru, I am sure I would replace my heavy sleeping bag with something much lighter saving close to 2 lbs.