Reddit mentions of The Westminster Assembly: Reading Its Theology in Historical Context (Westminster Assembly and the Reformed Faith)

Letham's book on The Westminster Assembly comes highly recommended, although I can't say I've read it yet.

You may also find some value in the Jerusalem Chamber podcast, which is going paragraph by paragraph through the confession in a panel discussion.

"Confessing the Faith" was a great read, but do be aware that Dixhoorn strays from the facts in at least one instance (when he suggests that the divines were divided on the idea of a 24-hour day in creation - there is no evidence to suggest this is the case). Outside of that I found it to be a great devotional read and hope it's a blessing to you :)

I'm currently reading:

• William Tyndale, The Obedience of a Christian Man (grr anthrocentric title ;))
  
• David Jennings, Sermons Upon Various Subjects Preached to Young People
  
• Henry Clay Trumbull, Hints on Child Training
  
  And a number of various history books. And as of today, I have a great desire to read Robert Letham's The Westminster Assembly, but I am dubious as to whether I can justify the cost thereof. :)