Thoracic mobility help arch ups?

My question is about the thoracic stretch course.  I seem to have difficulty progressing with my arch ups (SL/PE 6).  It seems like I could progress faster if the front side of my torso was more mobile (my extensors seems like they are working too hard).  

Would the thoracic stretch course be the best option for this?

Without a doubt!

Thx.  

I assumed that would be true but wanted second opinion

No problem Chris.