Wood will shoot straight even if the shaft itself isn't perfectly straight as long as the nock and point are on straight. Can't say the same for aluminum. Of course, carbon doesn't take a set. It's either straight or broken. Regardless, though I've incorporated carbons into my shooting and hunting, I shot wood for more than 50 years and killed a lot of critters with wood. I'm certain that not one of my misses was due to using a wood arrow. They were all me.
Regarding the greenwood shafts, I don't know why/how the impregnated birch footing can weigh 100 grains more than the laminated birch footing, which is the difference between the two arrow weights with the different footings.