If you start using shrinkies, I suggest getting the "rough and ready" kind (they call them that, not me), that are not slick on both sides. I used to use them, I never remember having a curling problem, and didn't realize it would be an issue when I bought the ones that are slick on both sides. It was a nightmare.
They only have that kind in the store in our city so that's good ^^
You have to put the rough side up (wasn't it?) so they curl up and if they are a bit bubbly, I smash them flat with a spoon, *go spoon*