Here is what I did on our last trip, in May '08 - and we lucked out. Ohanas was fully booked so I made a reservation instead at Kona Cafe and we were all fully OK with that (if slightly disappointed), because we really wanted to go to the Poly one night. When we arrived at around 6:00 for our 7:00 Kona reservation, I asked at the Ohana podium if they had any cancellations and could seat us (4 people). They did! We had about a 15 minute wait, and once I knew we were definitely going to be seated, I popped next door and canceled the Kona reservation with the hostess (she was fine with it). After all that, the food at Ohana was not even that good, IMHO. But my son loved the entertainment and we loved the exotic drinks. So, give it a shot if you really want to go, but have a Plan B just in case.