Muslin help for Saint Germaine dress

Hi friends at Liesl & Co. I followed Masha's suggestion and sewed a muslin of the Saint Germain in size 10 B cup and then in what my high bust is (35") in Size 8 C cup.I took photos of all side of each. I am a bit intimidated as to where to go from here. the 8 seems to fit in the shoulders and neck area much better, however it is still tight at bust. The lower back seems to have a lot of fabric, and at same time I wonder if I have the forward shoulder thing going on. Ackk! Could I email anyone the photos of the size 8 and size 10 for some advice as to where to start - which alteration first. I have looked at the tutorials for all the different ones Masha and Camelia did. Just need help to get pointed in the right direction. Nirmala