Use Create Ad Variation

Located under the Drafts and Experiments section, Ad Variation is another tool in Google Adwords which helps you to streamline ad creation and testing. Once you click blue “plus” button, you’ll get detailed options such as view what campaigns it affects, the ad you are making the variation to, and all the other details it needs to get set up.

The best part is you have the ability to set up the percentage split of your audience which enables you to set a 50/50 split & is auto optimized by Google