Help choosing zize

Hi! I am planning to try out the Saint-germain wrap dress this spring, but I am stuck with which size to choose as a starting point for my muslin. The main concern is the size for the top. My measurments are High-bust: 38,5, Bust: 42,7, Waist: 36,5, Hips: 44. I am thinking I should choose a size 12 and the D-cup. But in the finished measurements list on my printed pattern it says that the bust measurement for size 12+D-cup is 41,25 inches... so I am confused. Should I still use size 12 as a starting point and make an fba? Hope you can give me a hint. Kind regards Piia