We book ADRs using two devices--one signed onto the website, the other using the
MDE app. Generally, if one freezes or crashes, the other will still be usable. DH handles the bookings on both, generally entering what we're trying for on both since one may be faster.
I have a Note on my iPad with our hoped-for meals, ranking them in order of hardest to easier for the ones we know will be difficult to get. I tell DH what to go for first, next, etc., plotting by which days we have park reservations. We schedule breakfast and lunch in the park reserved or at a resort and then dinner wherever since we always get ParkHoppers to be able to switch for where we really want to eat.
I would head immediately to the last few days of your stay for a better chance to get 'Ohana dinner and work back from there.
Unless that dinner is particularly important to you, you may want to consider that there have been several reports recently of inferior quality meats and people feeling rushed through the meal. Something to think about, anyway, and maybe consider starting a new tradition. 'Ohana breakfast, maybe?
Whatever you decide, good luck getting the ADRs you want and enjoy.