Oooh, oooh I think I can answer
1. Yes I have experience with them.
2. Yes they work.
3. Pretty much the same way you would use a crimper.
We used these for a lot of shows in 2005. When we wanted the waves to stay perfectly wavy, we would spray a 2-3 inch wide piece of hair with hairspray before ironing. Then iron, starting at the top, to the bottom.. and everytime you move down the hair with the iron, you make sure to line up the uppermost barrel with the wave that was previously made with the lowermost barrel, or it doesn't look right. (I really hope that sentence makes sense to you!
) Then when done, spray with hairspray again. That creates really stiff waves, and also gets the barrels all icky.
I did it a few times on my hair (with no product, I sprayed my entire head with hairspray once it was done), and the end result was a really nice, natural-looking wave. I have naturally very thick and straight hair.
It's hard to do it yourself though, when it comes to the back of your head. It's *so* helpful to have a friend to do it for you. It also takes forever if you have thick or long hair. It took me at least an hour with bra-strap-length hair. Oh, and make sure your hair is fully dry before you put the iron on it
Hope this helps!