Thanks for writing in! Just for future topics, self responding or bumping your post pushes it back in our Queue system so it takes longer to respond to.
Please keep in mind that X theme is good for newbie and intermediate users. The demos and the customizer manager will help you easily start your own site by utilizing the demos or use the customizer manager to have the same X theme settings from one installation to another site installation.
Pro theme on the other hand is good for intermediate and advance users, designers, developers or someone who want to create something beyond X theme especially in lay-outing the header or footer.
If you re unsure and want to use the demo contents first, you may install X theme first, import that demo contents and switch to Pro theme after. This could save you time if you want to have a site similar to one of our demos with the modified headers or footers.
By the way, you can use X and Pro license for the same site. Just remember that you can only activate one theme in WordPress at a time.
Hope this helps.