PC1271 on "[Plugin: WP Blog and Widget] Template of blog post cannot be changed"

On the blog post admin panel, there's no way to change the template for the blog post. At least, I don't see it.
I would like to show most blog posts full width or without sidebar. For some others, it would be nice to have a left or right sidebar. The standard post template or a custom made template with different sidebar.

I know how to create a custom templates, but if there's no way to assign them to the blog post, there's not much sense in creating a custom template.

So, my question is: how can I assign a template for individual blog posts?

https://wordpress.org/plugins/wp-blog-and-widgets/