I don't like edgie wedgies, and use them as a fall back only.
It's vital to NOT take the kid onto slopes where they are using a whopping great snowplough. Stay flat.
If I'm using one, I try taking it off for short periods, to see if the pizza is happening yet. If it's one on one, I give the kid one end of my ski pole, and we use it like handlebars. The kid can glide around and at some point, they start to pizza, but they pizza for turning, not for stopping.
I have never liked the movement patterns that edgie wedgies produce, the way they have the kid bracing out against the outside of their boots, and the way they promote a breaking wedge rather than steering the skis around the place. I do understand that sometimes they are necessary, but should be carefully used. If it's one on one, try using the pole as well. It has many positive effects.