No. You do not need to act as a contact or add one just to preview a microspace.
You can preview the microspace using the View button in the editor. This opens the microspace in view mode, where you automatically see what it looks like from a contact’s perspective. If you use personalization tokens, it will show your own name to show how the contact will see the content.
To check how your microspace looks on different screen sizes, use the responsive preview switcher in the top bar of the editor.