Muslin #2.....getting closer

Huzbear Brian came over yesterday to help in the garden and agreed to take pictures of me in the new and improved fitting muslin.  So I donned a flannel shirt and sweater, thank God it wasn't hot, and modeled the new version.  The alterations I've made so far are a step in the right direction, but I'm still not convinced that it's fitting right.  I think the shoulders are better and I like being able to close it in the front. That MAY come in handy this winter!  It may still be a bit tight across my chest.  The back is a complete mystery.  Of course it doesn't help that I can't see back there.  Brian thinks that the armholes are too small, and I'm tending to agree with him there.  Maybe if I chop out about a 1/2" from the bottom of the arm opening, it would stop bunching up in the back?  Thoughts from any followers would be appreciated.  In the meantime I'm going to be researching how to change the armhole.  This seems like very treacherous territory to me.  The coat has a 2 piece sleeve, and its seam doesn't line up with the side seam of the coat.  I feel like I need to call my Jr. High geometry teacher.