Does the layout system you're using allow for em dashes? If I'm composing in Google Docs and insert each em dash as a special character, will that cause problems on your end? Is there a better solution? (I've been using double hyphens, but it looks ugly and I'd rather not.)
Keep using double hyphens! The layouting software will turn them into em dashes automatically, as that is the way these special characters are expressed in the code. (At any rate I will check that they end up as em dashes. I tend to overuse dashes in my own writing, so I know I’ve encountered similar problems.)
But if you already have em dashes as special characters in your writing, don’t worry either. You needn’t change anything. It’s a simple thing to fix via search and replace.