This post will be the thread where we solve this. For now my easiest suggestion will be the usage of Advanced Custom Fields (ACF). This is a free plugin that allows to define Meta values for posts and pages. In it’s latest release it will also feature Blocks with some easy helper.
Read this announcement (currently only a Beta for Pro-User):
The code looks pretty straight forward.
I’ll keep you posted once this feature is out for the free version and we can create Hype-Gutenberg-Blocks with it.