Grid/Column layout: Fixed-width sidebar or sidebar is within the column grid?

This question is regarding grid layout, the context is that I am designing for a platform which has a pinned sidebar on the left. I'm trying to figure out the layout settings.

According to this article, near the bottom of the article, it wrote that 'Dashboard with pinned sidebars are the perfect example of the fixed-width sidebar layout.'

However, the issue comes when the platform I'm designing for also has a frame that has 2 sidebars (1 left and 1 right). So should I set my layout as the above (since I have a pinned left sidebar) or should I have all my sidebars on the columns? As of below.

(2 sidebars)

1 sidebar (left)