Yes, I would say not to bother trying to just cut. I've tried holding a head still to clean junk out of an eye before, and it's not easy. You'd need three hands to cut a head off, and I assume that your mother isn't going to lend that extra hand, lol. You really don't bop them hard, just hold them with your thumb on their breast and fingers around the body to cover the wings. The bird should be facing you. The force is really just slightly more than gravity pulling your arm down. You don't want to crush their skulls, just knock them out. They'll go limp and their necks will stretch out, making it very easy to get shears in place. There's maybe a teaspoon of blood that will come out, and they're not violent shakers, just a little bit of vibration.
Hens should give you an egg per day. Rarely will they miss a day. If you have 20 hens, you should get 20 eggs per day.
Just do one breeding group, either put the eggs in the incubator or put them in the fridge, depending on whether you want to eat the eggs or grow them out for meat. That will make them more versatile.