If you do want an early breakfast at Kona, make an ADR. It is not that you'll have a problem getting a table, but it will *ensure* that they are open right at 7:30. Here's why I say this: we'd made reservations there for 7:30 breakfast our first trip, and thought, because there were so many open tables, that it wasn't worth our trouble to make the ADR for our second trip. When we arrived that second time, we were informed that they would open at 8 for breakfast, even though the published time in the hotel's own newsletter/guide said 7:30 (staff were all there, hanging out, having their a.m. coffee, chatting together, etc.). I cannot say this for a fact, but it *apppeared* to us that, because there were no early reservations, they decided to open up 30 minutes later. Now, I am saying that we made this deduction, so no flames if I'm incorrect ;-). But, it would seem fair to say that thee ADR protects your early morning breakfast time, if that's indeed what you are counting on.
In any case, Kona is a must-do for us -- hope that you enjoy it, too!