For anyone curious as to the weight of the vague ingredient amount, “a bunch of curly kale,” I have measured and calculated some averages to be used heuristically.
Between two bunches of kale, I found that the average kale leaf weight (minus stem) = .4 oz.
Average stem weight = .2 oz
My bunches weighed 6.75 oz and 6.2 oz with stems and leaves intact.
Thusly, if your bunch of kale has 10 leaves, the bunch will probably weigh around 6 ounces, which is the average weight of a bunch of kale, I believe.
For recipes, try to buy kale in ~6oz bunches so that you can get 4oz of actual kale leaf from it to use.
Conclusion: average weight of bunch of kale with stems at a store = 6.5oz.
Now, the mystery is over for you chefs.