I agree with the pp that it all depends on how busy it is at the time, but I think your chances of getting seated right away are pretty good since your ADR is just a half hour after opening. With that said, we have eaten at Chef Mickeys many times over the years and usually get seated right away or just shortly after checking in (we always get an early ADR time and arrive at least 15 minutes early). With that said, the only place we have ever had to wait until our ADR time (regardless of what time we arrive) is Boma.