What is the covering?

Almost every covering can be applied such that the wrinkles will come out with the heating our irons can provide.

So why not iron them out? If raising the heat a little at a time doesn't do it, then it's worth the lesson to pull it off and apply fresh covering. Apply tightly enough that it's shrinking ability removes the remaining wrinkles.

Why would you want to leave wrinkles that might iron out. And if they won't, it's worth your effort to learn to cover without wrinkles. And to produce a model with a covering job that will actually add strength and not cause drag. The added strength isn't a lot, and the drag isn't huge. But you'd cut a better piece out of balsa if the 1st wasn't large enough wouldn't you?