The Spencer itself is an interesting combination of both a fitted back and drawstring front. Drawstring bodices were typical of the transitional clothing of 1790s. It maintains the center back seam and separate shoulder straps of the 18th c construction but the flairs at the back seams flirt with future construction styles.
FIT:
The very high period waist is higher than what a woman in the 21st century would wear and cannot be easily achieved without some form of corsetry. This spencer would have been worn over a shift, stays, and with at least one bodiced petticoat or gown.
FABRIC:
The original fabric is a light cotton with a soft drape. The pattern works well in various weights of cotton and silks.
CHOOSING SIZE:
When deciding which size is correct for you to use, measure your rib cage under your bust, preferably with your stays or corset and underpinnings on. This is the single most important measurement. This waistline has 1” ease and is meant to fit snugly to your body. With drawstrings to adjust fit, it can accommodate a variety of bosoms.
Sizes 8 - 18 or 18 - 28