True slyfox, no two people are built alike, but there is only one way to lip squeak and it's not that hard to do, heck I can do it and I'm not the smartest guy on the planet.
I learned from the same guy Rich Cronk did, Rich learned in person and I read about how to do it.
Of all the sounds a person can make without a call to attract predators, I do believe the lip squeak is by far the best. I also believe if a person is a serious caller they should learn how to do it.
I also believe the more tricks you have in your bag the better.