What technique?

the spray on aerification etc. basically has anyone used any of these products with success...

Absolutely. They work so well I have stopped all other methods. I even stopped using the method I invented because they work so well. There are two popular types of spray on "aerification" products. One is soap and the other is enzymes. The soap costs more than the enzymes. Both work.

If you want to save a bunch of money, get some generic baby shampoo and spray your lawn at a rate of 3 ounces of soap per 1,000 square feet. If you don't know how to use a hose end sprayer, let us know and we can help with that. Any clear shampoo type soap will work. Do not use soap with antibacterial stuff in it.

Does the baby shampoo method affect or kill the worms that may be in the soil? I'm thinking about trying it, but don't want to harm any worms I have working in there. Thanks.

I'm not sure anyone has the definitive answer to that. I don't go digging around for worms, but I do occasionally see them surfacing if we get a heavy rain. If you are concerned about that you can ditch the soap and try natural surfactants like yucca extract. I realize you live in the land of yucca but might not be able to find it locally. If so then the Nature's Lawn site might have what you are looking for.