Current student here, thought ya'll should know that the tentative fall schedule is online:https://www.law.umich.edu/currentstuden ... ?term=2060
Obviously you don't know your sections until summer (except summer starters, who are large section ABCD) so you won't know the exact profs or classes you will have, but you can still take a peak at what it might look like.
In terms of what these section divisions mean - everybody is assigned to a single letter section, consisting of 20-25ish people. This section will meet by itself for legal practice classes. For two of the fall doctrinal classes, four of these sections will be grouped into a large section. For the third doctrinal, two of the sections are grouped together into a mid-sized section. I don't know if it will be the same this year, but for the winter semester there is typically no longer a mid-sized section, it's simply 3 doctrinal classes with your large section in addition to the 2nd semester of legal practice.
They're doing things a bit differently than this year's class in terms of fall starter's class schedules. For c/o 2018, all sections will be enrolled in torts as their mid-sized class, c/o 2017 all had civpro as our mid-sized class. Two of the large fall starter sections will also have leg/reg for fall semester - all of c/o 2017 were spared that class until this current semester.