You can look at the st number differences between sizes and go down a 'size' that way. Say there's 8 sts difference in the CO number between sizes, you'd CO 8 sts less than the Med. Look at the schematic first for the measurements given. Could be this pattern runs small and the Med would fit you. You have to go by the measurements, not be someone's arbitrary lable of S M L XL or whatever.
sue- knitting heretic