I generally draft the sleeve in a separate block.
If you were to draft the sleeve in the same block as the bodice I would definitely put the bodice and sleeve parts in seperate groups that will allow you to toggle on / off which parts you want to see at any given time. In fact, your’re going to want to make use of groups in general. For example… lets say you draft a sleeve in it’s own block, with a long and short version. You can put the objects that make up the long sleeve in one group, and the objects that make up the short sleeve in another. Now you can choose to see the long sleeve, the short sleeve, or both.