I don't know what to do about the hulls, but I "helped" a friend's dad harvest almonds when I was in the 3rd grade.
Friend and I were asked to climb up the tree and wait. The dad spread sheets underneath the tree.
Then he said, "OK, girls, hang onto a branch and jump up and down carefully. Jiggle the almonds off the tree!"
And there were absolute showers of almonds onto those sheets. I even got a sackful to take home on my (first) bicycle.
It's stuck with me ever since as an excellent way to harvest nuts: put sheets down and borrow a couple of kids. (Not that I've had the trees to do it with, but it's a great idea.)
Perhaps others will help with the walnut hulling process.
USDA Zone 9, Sunset Zone 17