Heading tags in wordpress theme

I know we should put the website name in H1 tag and posts titles in H2 tag IN HOMEPAGE.

What about Single post pages? Which one is better?

1. 
   

   Website Title in H1 and Post title in H2

   
   


2. 
   

   Post title in H1 and use H2 in the content.

   
   

I think second one is better so consider this question too: Does second one worth it?