I am making a muslin for a blouse and have discovered that my arm circumference is 2″ larger than the size I am cutting. Do I slash the sleeve at the top and add the entire amount here? or should I add at the top of the sleeve (1″) and at the bottom of the sleeve (1″ ) Would I then make the same corresponding changes to the blouse front and back? I also have a broad back (which I made a slash and added fabric in the back for), but it also seems that I have hollow upper chest (above the bust) because the fabric is kind of bagging out above the bust? Any suggestions? The last blouse I made (different pattern) fit okay, but the arm feels small above and at the elbow, but the armhole itself fits well. Thanks !