I'd honestly just get sketchy micro. I read CMMRS before I did sketchy, and while it filled in the gaps in my school's micro curriculum (of which they are many), the details fell right out of my head shortly afterwards until sketchy hammered them in for good. I think I would have gotten just as much out of sketchy without CMMRS beforehand, but CMMRS without sketchy would NOT have cut it at all. FWIW I'm in boards prep right now and I would consider micro possibly my biggest strength (backed up by NBME results), and when I started UWorld it was my lowest scoring section next to pharm.